March 13, 2009

March 13, 2009 - March 13, 2009 This is now a heat machine...

Info iconThis preview shows pages 1–7. Sign up to view the full content.

View Full Document Right Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: March 13, 2009 This is now a heat machine 23Latm our 17 used to return piston at colder temperature 23-17 = 6 = extra work available to turn a wheel. Summary draw in heat at hot temperature and it does work T constant so no E Total work divides into useful work and heat returned to surroundings (waste heat of power plant fame) when compressed at lower T ( T c ) Main equation Work done/heat absorbed at T h = w/q h = (T h T c )/T h For T h = 400K and T c = 300K w/q h = (400 -300)/400 = 0.25 of all the heat converted to useful work (anther name free energy) 2 = (1000) = 250J Remainder 750 J is waste heat. If pull in 1000J of heat at T h = 400 Greater fraction turned to work if T h is higher Steam engine water vapor 400K surroundings 300K of energy used Diesel T h =500K w/q h = (500-3)/500 = 200/500 = 0.4 Extreme case solar energy T h = T sun = 6000 T earth = 300K w/q h = (6000 300)/6000 = 57/60 = 0.95 of solar energy received could potentially be turned into work Use T...
View Full Document

Page1 / 12

March 13, 2009 - March 13, 2009 This is now a heat machine...

This preview shows document pages 1 - 7. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online