Berkeley CSUA MOTD:Entry 45973
Berkeley CSUA MOTD
 
WIKI | FAQ | Tech FAQ
http://csua.com/feed/
2025/07/08 [General] UID:1000 Activity:popular
7/8     

2007/3/15-20 [Science/Electric, Science/GlobalWarming] UID:45973 Activity:low
3/15    According to ABC, 90% of the energy used by incandescent bulb is
        wasted in heat.  That mean only 10% of the enery it takes in
        outputs useful light. In addition compact flourescent light takes
        about 1/4 of the same energy for the same output. So let's suppose
        I have a 25W compact flourescent bulb and outputs as much as a
        100W incandescent bulb (or 10W of useful light). Can I safely
        assume the compact flourescent bulb also outputs 10W of useful
        light and 15W wasted in heat, or 10/25 (40%) efficiency?
        \_ I'm sure that will make a major diff. in 'saving the planet'
           Of course it won't. The only real way is population control.
           \_ 36 years old and no kids yet.  Can I have a tax break?
        \_ of course in winter, the 'heat' isn't wasted.
           \_ Yeah.  But in summer, not only is the heat wasted, it makes your
              AC work harder which takes even more energy.
           \_ not entirely -- except when you consider the energey used to
              generate that electricity in the first place.  Usually generated
              by some form of heat engine, again usually burning fossill fuels.
              So that 90W of electrically-created heat required the waste of
              another ~200W of heat at the power plant.  Compare this to
              burning gas locally to generate heat, where virtually all the
              heat in the gas goes to heating.
              \_ totally agree. But neither heat nor power generation is
                 factored into light bulb efficiency anyways -pp
           \_ Yeah.  But household furnace usually burns natural gas.
              Burning gas to generate heat is more efficient than burning gas
              to generate electricity and then using electricity to generate
              heat, which in turn is cleaner than burning coal to generate
              electricity and then using electricity to generate heat.  Also,
              in summer, not only is the heat wasted, it also makes your AC
              work harder which uses even more electricity.  That's the same
              reason why, if you leave your PC and monitor idling at, say, 20W
              in an air-conditioned room, you're actually wasting more than
              20W.
              in an air-conditioned room, you're actually using more than 20W.
2025/07/08 [General] UID:1000 Activity:popular
7/8     

You may also be interested in these entries...
2014/1/24-2/5 [Science/GlobalWarming] UID:54765 Activity:nil
1/24    "Jimmy Carter's 1977 Unpleasant Energy Talk, No Longer Unpleasant"
        link:www.csua.org/u/128q (http://www.linkedin.com
	...
2012/12/7-18 [Science/GlobalWarming] UID:54550 Activity:nil
12/7    Even oil exporters like UAE and Saudi Arabia are embracing solar
        energy: http://www.csua.org/u/ylq
        We are so behind.
	...
2012/6/22-7/20 [Politics/Domestic/California, Science/GlobalWarming] UID:54420 Activity:nil
6/22    "Study: The U.S. could be powered by 80% green energy in 2050"
        http://www.csua.org/u/wtz  (news.yahoo.com)
        \_ How many Republicans does it take to make green energy?
           -150,000,000! Ding ding ding!
           \_ Because having control of the White House and both houses of
              Congress wasn't enough (ie, the do nothing and blame the
	...
2012/6/26-7/20 [Science/GlobalWarming] UID:54422 Activity:nil
6/26    WW2 brought us antibiotics, syringe, production capacity,
        excessive petroleum, radar, television, atomic energy,
        rocketry (HEIL VON BRAUN), synthetic rubber, microwave,
        computers (GAY TURING), jets.
        What did the Iraq war bring us?
        \_ HMMWV -> Hummer H1 the gas guzzler.
	...
2011/2/1-19 [Politics/Foreign/Asia/China, Science/GlobalWarming] UID:54022 Activity:nil
2/1     10 Industries in Which the U.S. Is No Longer No.1"
        http://www.csua.org/u/sgw (finance.yahoo.com)
        China betas us in 7 out of 10 categories, including high-tech exports
        category.
        \_ So, only 3 more to go until we declare war?
        \_ Some of those positions are simply determined by
	...
2010/12/2-2011/1/13 [Science/Space] UID:53986 Activity:nil
12/2    'Starry, starry, starry night: Star count may triple'
        http://news.yahoo.com/s/ap/20101202/ap_on_sc/us_sci_starry_night
        'So the number of stars in the universe "is equal to all the cells in
        the humans on Earth, a kind of funny coincidence," Conroy said'
        Another coincidence is that 1 mole = 6.02 * 10^23.  So the number of
        stars = # of molecules in 1 gram of H2 gas.
	...
2010/12/1-2011/1/13 [Science/GlobalWarming] UID:53987 Activity:nil
12/1    "US: China rise a 'Sputnik moment' for clean energy"
        http://news.yahoo.com/s/afp/20101130/sc_afp/unclimatewarminguschina
	...