IntroGrand Challenges in Engineering- Making solar energy economical- Providing nuclear energy from fusion- Access to clean water- Restore and improve urban infrastructure- Cyberspace security- better medicines- Water-Energy NexusOrigins of Env. Engineering- Water filtration and transportation- originally called sanitary engineering- humans impact well-being of environment and vice versaSocial – Economical – Environmental- Protect human health- protect the environment- water, air, soil, waste, energySustainable Development – meeting needs of today without comprising needs of futurePopulation & GrowthOverpopulation is an environmental problemPopulations – number of organisms of same species in a particular area- influences – resource use and waste productionLogistic growth is governed by carrying capacityFactors – resource use and distribution- technological innovationGlobal Population is affected by age structure, industry, economy, resourcesDemographic Transition – transition from high to low birth and death ratesEcological Footprint – how much we needBiocapacity – how much we haveNOT evenly distributedEnergy & HeatEnergy – ability to do work (Joule)Uses for energy = electricity, transportation, industryPower – rate of energy consumption (watt = joule/second)Total energy = internal (chemical, thermal) + mechanical (kinetic, potential)Heat Capacity – energy transfer from system to surroundings- amount of energy needed for a temperature changeSpecific Heat Capacity – depends on size of the systemQ=m*C*dT Q=m*FFuel Sources – oil, coal, natural gas, nuclear, renewablesHeating value – amount heat released in combustion of substanceHigher Heating value – amount head released in complete combustion of substanceCarbon Cycle, Greenhouse Gases, Climate ChangeFossil Fuels – carbon based fuel sourcesExamples – coal, natural gas, petroleumCombustion of fossil fuels  Fuel + O2 -> Water + Energy + CO2Carbon Cycle – transfer of carbon through the biosphere, hydrosphere, atmosphere, geosphereBased along biological and geological systemsThere is more carbon entering the atmosphere than leavingMore carbon in atmosphere during winter – less trees to perform photosynthesisGreenhouse Effect – increased temperatures due to trapped carbon dioxide in atmosphereAbsorb long wave radiation and convert it to heatClimate Change – increased temps, more intense storms, ocean acidification, glacier melting- food web disruption, habitat destruction- What can be done? Mitigation (reducing CO2 emissions) and Adaptation (live with these changes)Fossil Fuel and Chemical ThermodynamicsCombustion – oxidation with O2 to release energyCarbon Sequestration – natural biogeochemical cycling of carbon – removal of carbon from atmosphere, deposition to reservoirEnthalpy < 0 – energy is released into atmosphere EXOTHERMICLook at how to calculate energy loss, etc.Biomass FuelsIdeal energy source – plentiful, renewable, easy to use and obtain, inexpensive, safeAlternative Energy – energy from a source not a fossil fuelRenewable Energy – energy from a source that is continuously replenishedBiomass Energy – stored in organic matterAgricultural, sewage, forestry, animal residues (wood, corn, wheat, maure)Biomass contains carbon, oxygen, hydrogenDirect Combustion – evaporation of water, anaerobic burning, then combustion to get energyGasification – produces syngas (gas mixture of hydrogen and carbon monoxide)Biochemical Conversion – Fermentation – sugar to acid, gas, alcohol with yeastAnaerobic – hydrolosis, acidogenesis, acedogenesis, methanogenesis (forms biogas – carbon dioxide and methane)Carbon footprint can be zero, but isn’t alwaysPros of Biomass – renewable, clean, zero carbon footprint, less national dependenceCons – less efficient, land requirements, food demands of resourcesSolar PowerSolar Power – photovoltaic cells, concentrated solar power- Solar PanelsDon’t store energyUses a semiconductor – photon hits panel, energizes charges so electron can jump band gapDoping – increase in conductivity to ensure the electron jumps the band gapLow efficiency – not all electrons carry enough energy to jump band gapIncrease efficiency by using different metals and multiple metals to give multiple band gaps- Concentrated solar power – lots of lenses and mirrorsSolar Thermal – water heating, HVAC, water treatment, agricultureSolar Chemical – artificial photosynthesis, water splittingPros of Solar Power – renewable, clean, endless supply, no carbon emissionsCons – low efficiency, no storage, land use, variable sunlight, expensiveWind PowerForm of solar energy – uneven heating of earths surface creates wind thru pressure differencesHorizontal Turbine – more efficient, standard ones you seeVertical Turbine – not dependent of wind directionKinetic energy of wind turns blades – mechanical energy – spins shaft in turbine, connected to generator that converts to electrical energyWind energy fluctuates per season, stormsStorage – compressed air, chemical fuel, flywheel, hydropowerPros – renewable, clean, endless supply, low operating costCons – land requirements, limitation of sites, environmental concerns, noise, lower efficiency Hydroelectric PowerFalling or flowing water – comes into dam and spins a turbineImpulse turbines – high head and low flow (falling water)Reaction turbines – low head and fast flowPros – emission free, renewable, high efficiency, low maintenanceCons – land reqs, impact on ecology, variable power, high initial costNuclear EnergyTypes – pressurized water, boiling water reactorHeat produced by fission generates steam that turns turbinesSplitting of 235 isotope occurs in the reactor core (100s of fuel assemblies)Isotope – different number of neutronsUranium – main ingredient – obtained thru mining, enrichment, and fuel fabricationNuclear fusion – colliding 2 nuclei to get a new nucleusNuclear waste – most is harmless, but about 3% is toxicPros – cost efficient, reliable, clean, alternativeCons – dangerous, waste disposal, radiationBinding Energy – energy needed to break nucleus and separate protons and neutronsMass Defect – difference b/w mass of nucleus and mass of nucleons that comprise itRadioactive decay – disintegration of nucleus to release energy - Alpha, beta, gamma decayGeothermal EnergyObtained from the earthDirect Use Geothermal EnergyPump water