These are totally made up figures, but they illustrate the point.
Say 1 million CDs are sold last year. A 2.2% decrease is 20,000 CDs. If 100 CDR were sold last year and 229 are sold this year, then CDRs increased by 129%.
The moral? Don't ever believe percentages on their own. Especially if there's no sample size given.
Actually, recovering the exhaust heat - typically to produce more steam which in turn is used to make more power via another steam turbine - is called cogeneration. (The example I just gave is called "combined cycle".)
It's fairly common (although not as common as a standard condensing steam turbine power plant is). It's also significantly more efficent. A standard condensing plant is on the order of 30% efficent, whereas a combined cycle plant is more than 50% efficent.
If you can use the exess heat for something other than making power (i.e. district heating) the overall efficency of the plant can be as high as 75%!
Slashdot Mirror
Say 1 million CDs are sold last year. A 2.2% decrease is 20,000 CDs. If 100 CDR were sold last year and 229 are sold this year, then CDRs increased by 129%.
The moral? Don't ever believe percentages on their own. Especially if there's no sample size given.
Actually, recovering the exhaust heat - typically to produce more steam which in turn is used to make more power via another steam turbine - is called cogeneration. (The example I just gave is called "combined cycle".)
It's fairly common (although not as common as a standard condensing steam turbine power plant is). It's also significantly more efficent. A standard condensing plant is on the order of 30% efficent, whereas a combined cycle plant is more than 50% efficent.
If you can use the exess heat for something other than making power (i.e. district heating) the overall efficency of the plant can be as high as 75%!