Tuesday nights State of the Union Address: President Obama At this moment, with a growing economy, shrinking deficits, bustling industry, booming energy production, we have risen from recession freer to write our own future than any other nation on Earth. Its now up to us to choose who we want to be over the next fifteen years, and for decades to come. We believed we could reduce our dependence on foreign oil and protect our planet. And today, America is number one in oil and gas. America is number one in wind power. Every three weeks, we bring online as much solar power as we did in all of And thanks to lower gas prices and higher fuel standards, the typical family this year should save about $750 at the pump. US Wind Power: 2008: 8,366 MW 2009: 10,010 MW 2010: 5,216 MW 2011: 6,810 MW 2012: 13,131 MW 2013: 1,084 MW 2014 (Jan-Oct): 1,254 MW, with >13,600 MW under construction And thanks to lower gas prices and higher fuel standards, the typical family this year should save about $750 at the pump. Our manufacturers have added almost 800,000 new jobs. Some of our bedrock sectors, like our auto industry, are booming. But there are also millions of Americans who work in jobs that didnt even exist 10 or 20 years ago: jobs at companies like Google, and eBay, and Tesla. And no challenge, no challenge, poses a greater threat to future generations than climate change was the planets warmest year on record. Now, one year doesnt make a trend, but this does: 14 of the 15 warmest years on record have all fallen in the first 15 years of this century. Ive heard some folks try to dodge the evidence by saying theyre not scientists, that we dont have enough information to act. Well, Im not a scientist either. But you know what? I know a lot of really good scientists at NASA and at NOAA and at our major universities, and the best scientists in the world are all telling us that our activities are changing the climate, and if we dont act forcefully, well continue to see rising oceans, longer, hotter heat waves, dangerous droughts and floods, and massive disruptions that can trigger greater migration and conflict and hunger around the globe. The Pentagon says that climate change poses immediate risks to our national security. We should act like it. Thats why, over the past six years, weve done more than ever to combat climate change, from the way we produce energy, to the way we use it. Thats why weve set aside more public lands and waters than any administration in history. And thats why I will not let this Congress endanger the health of our children by turning back the clock on our efforts. I am determined to make sure American leadership drives international action. In Beijing, we made a historic announcement: the United States will double the pace at which we cut carbon pollution, and China committed, for the first time, to limiting their emissions. And because the worlds two largest economies came together, other nations are now stepping up, and offering hope that, this year, the world will finally reach an agreement to protect the one planet weve got. Thats why, over the past six years, weve done more than ever to combat climate change, from the way we produce energy, to the way we use it. Thats why weve set aside more public lands and waters than any administration in history. And thats why I will not let this Congress endanger the health of our children by turning back the clock on our efforts. I am determined to make sure American leadership drives international action. In Beijing, we made a historic announcement: the United States will double the pace at which we cut carbon pollution, and China committed, for the first time, to limiting their emissions. And because the worlds two largest economies came together, other nations are now stepping up, and offering hope that, this year, the world will finally reach an agreement to protect the one planet weve got. Thats why, over the past six years, weve done more than ever to combat climate change, from the way we produce energy, to the way we use it. Thats why weve set aside more public lands and waters than any administration in history. And thats why I will not let this Congress endanger the health of our children by turning back the clock on our efforts. I am determined to make sure American leadership drives international action. In Beijing, we made a historic announcement: the United States will double the pace at which we cut carbon pollution, and China committed, for the first time, to limiting their emissions. And because the worlds two largest economies came together, other nations are now stepping up, and offering hope that, this year, the world will finally reach an agreement to protect the one planet weve got. Thats why, over the past six years, weve done more than ever to combat climate change, from the way we produce energy, to the way we use it. Thats why weve set aside more public lands and waters than any administration in history. And thats why I will not let this Congress endanger the health of our children by turning back the clock on our efforts. I am determined to make sure American leadership drives international action. In Beijing, we made a historic announcement: the United States will double the pace at which we cut carbon pollution, and China committed, for the first time, to limiting their emissions. And because the worlds two largest economies came together, other nations are now stepping up, and offering hope that, this year, the world will finally reach an agreement to protect the one planet weve got. Table 3-1, p. 82 Fig. 3-3, p. 80 Table 3-5a, p. 94 Fig. 3-4, p. 83 Table 3-5b, p. 94 ? ? 10% Table 3-5b, p %18% It takes a LOT of energy to get water to change its phase (to get ice to melt, and to get liquid water to boil)! Fig. 3-3, p. 80 It takes a LOT of energy to get water to change its phase (to get ice to melt, and to get liquid water to boil)! Heat of Fusion: It takes 335 kJ to turn 0C ice into 0C water Heat of Vaporization: It takes 2260 kJ to turn 100C water into 100C steam How much energy does it take to turn 1 kg of 0C ice into 100C steam? E = 335kJ + (4.19 kJ/C)(100C) kJ = 335 kJ kJ kJ = 3014 kJ Fig. 4-7, p. 106 HEAT flow by three mechanisms: Conduction Convection Radiation CONDUCTION: k = thermal conductivity CONDUCTION: R = /k = R value Q c = A x (T 2 T 1 ) t R Table 5-2a, p. 134 Table 5-2b, p. 134 Equivalent thicknesses needed to provide an R value of R = 22 (ft 2 hr F/Btu) CONVECTION: RADIATION (Electromagnetic): Many energy-related machines are examples of a Heat Engine Transforms Heat into Work Ex/ Steam engines, combustion engine, heat pump (refrigerator or air conditioner) Efficiency = Work out x 100% Energy in Efficiency = Work out x 100% Energy in = (Heat in Heat out) x 100% Heat in Efficiency = Work out x 100% Energy in = (Heat in Heat out) x 100% Heat in = (T H T C ) x 100% T H Efficiency = (T H T C ) x 100% T H The HOTTER an engine runs, the more efficient it is. Efficiency = (T H T C ) x 100% T H The HOTTER an engine runs, the more efficient it is. Ex/ If T H = 400K and T C = 300K then Max possible efficiency = (400K 300K)/400K = 25% Efficiency = (T H T C ) x 100% T H The HOTTER an engine runs, the more efficient it is. Ex/ If T H = 400K and T C = 300K then Max possible efficiency = (400K 300K)/400K = 25% Ex/ If T H = 1000K and T C = 300K then Max possible efficiency = (1000K 300K)/1000K = 70% Efficiency = (T H T C ) x 100% T H The HOTTER an engine runs, the more efficient it is. Ex/ If T H = 400K and T C = 300K then Max possible efficiency = (400K 300K)/400K = 25% Ex/ If T H = 1000K and T C = 300K then Max possible efficiency = (1000K 300K)/1000K = 70% It can never be 100%! Second Law of Thermodynamics 1)Heat can flow spontaneously (by itself) only from a hot source to a cold sink. Second Law of Thermodynamics: 1)Heat can flow spontaneously (by itself) only from a hot source to a cold sink. 2)No heat engine can be 100% efficient; some heat always has to be discharged to a sink at a lower temperature Which of these will happen? Second Law of Thermodynamics: In ANY system, the result of an interaction will be an INCREASE in disorder (Entropy) Time has a direction! (toward disorder) Which of these will happen? How does an air conditioner work? What happens to a gas when you compress it? A heat pump (air conditioner, refrigerator) uses the trick that gases become hot when compressed, cold when expanded. 1. HOT HIGH PRESSURE A heat pump (air conditioner, refrigerator) uses the trick that gases become hot when compressed, cold when expanded. 1. HOT 2. Cools off HIGH PRESSURE A heat pump (air conditioner, refrigerator) uses the trick that gases become hot when compressed, cold when expanded. 1. HOT 2. Cools off 3. Ambient HIGH PRESSURE A heat pump (air conditioner, refrigerator) uses the trick that gases become hot when compressed, cold when expanded. 1. HOT 2. Cools off 3. Ambient 4. COLD LOW PRESSURE A heat pump (air conditioner, refrigerator) uses the trick that gases become hot when compressed, cold when expanded. 1. HOT 2. Cools off 3. Ambient 4. COLD 5. Warms up LOW PRESSURE A heat pump (air conditioner, refrigerator) uses the trick that gases become hot when compressed, cold when expanded. 1. HOT 2. Cools off 3. Ambient 4. COLD 6. Ambient 5. Warms up LOW PRESSURE You can also do this by changing the phase from liquid to gas and back again. The gas GIVES OFF heat when you compress it into a liquid and it becomes hot You can also do this by changing the phase from liquid to gas and back again. The gas GIVES OFF heat when you compress it into a liquid and it becomes hot The gas ABSORBS heat when you let it expand back into a gas