If I thought diesel was only going to average that for the rest of the life of my car, I'd be a happy man.
(Basic point remains unchanged though.)
I did the research and concluded that I was more or less wrong. Stellar fusion goes all the way up to iron - I had thought the energy balance was too low for normal starts to go that far, but that is for only certain values of 'normal stars'
yes, but he is right that stars go beyond carbon.
Prolly most don't, as stars have to be more than a few times the mass of the sun to go supernova. Our sun won't go supernova, f'rinstance. But in some billions of years it will go red giant and the earth will be swallowed up.
Yes - it's quite amazing really.
You know, reading what harry posts makes me wonder if he is not in fact
14 years old. He has this childish "if it's not white it must be black" mentality. No shades of grey and just ignore inconvenient facts.
Depends what you mean by very hot. UK coal and nuclear stations have no problems pumping water at 160 deg C. I'd call that more than a bit hot. Not steam temperature at the boiler outlet temperatures but still 'very hot'
It's *nothing* to do with pumping water into boilers.
Once condensate leaves the condenser it is heated in multiple stages of feed heaters before it even gets to the boiler feed pump. The appropriate inlet pressure, inlet temperature, and dissolved gas concentration are all what are needed to avoid cavitation in the feed pump.
The 0-60 mph 'benchmark' for a Leaf is 11.5 seconds. You'd be hard pressed to find another car of a similar size so poor. Unless it's also electric.
ISTR he claims to be retired, although that would not rule out regression.
Colin Bignell
Exactly.
Its all do with the basic issues of using steam as a working fluid at all.
you can't get it THAT hot, and it has to come out the arse end at something like 40-50 C.
Better efficiency comes from gas turbines, because the gases are like
1000C and the final steam circuit outflows are like 40-50C.The amaxim efficiency of a thermal engine is simple.
1 - (outlet-temp/inlet-temp) where both are in degrees absolute. So for a steam boiler at say 260C inlet to the turbines, and final condenser at 40C, the numbers come out to1-(313 /533) i.e. about 41%
Go to a CCGT at 1000C and it all looks different.
1-(313/1273) . i.e. 75%.That's the maximum theoretical efficiency. In reality it tends to be about 37% for top steam plant and 60% for a CCGT.
And of course the gas temperature (and effiiency) goes down in a CCGT when its throttled back to make way for harries solar panels and windymills, so burning yet more fuel for te same power output
Exactly.
he is a professional green troll, or very dim. Or both.
No one would dispute that petrol and diesel will continue to rise in price, but the GBP 20395 difference in purchase price between the mind numbingly boring Mitsubishi i-MiEV and the 'world beating' Dacia Sandero Diesel buys 14500 litres of diesel at GBP 1.40, that is 291 full tanks of diesel, enabling the Sandero to almost travel the average distance to the moon (900 miles short)
238,000 miles in a Dacia Sandero ought to be enough for anyoneYou could just buy the Diesel now if the prospect of price rises is of any concern. 14500 litres of diesel stored in wheelie bins, IBC's or a dedicated tank has to be a better long term bet than the prospect of a Mitsubishi i-MiEV with a buggered battery.
The Natural Philosopher wrote: [about harry]
The two are not mutually exclusive as witness the moron with a double-barrelled name on R4 this morning talking utter bollocks about "fracking". He was shot down in mid flight by the prof. who pointed out that fracking has been happening in the UK for decades with no bad effects. Also that fracking is an essential process in hot rock geothermal energy systems.
Your turbine steam inlet figures are way out compared to the standard in the UK
568 deg C / 168 bar is the norm for HP inlet for all >120MW units with final stage steam temperatures of around 30 deg C.That makes the ideal Carnot efficiency closer to 64% with as you say 37% being about the norm for real life.
Fairy nuff. I haven't had much to do with steam plant since I leftcollege :-)
So actually that makes sense. actuall eff is about 80% of carnot.
Yes there were. I spent forty years running steam boilers.
...
Obviously, not very well designed ones.
Colin Bignell
You can pump it at whatever temperature as long as the pressure is sufficient to prevent cavitation in the pump(s). And feedwater heaters are downstream of the pump for that very reason.
Condensers are in fact working at sub-amospheric pressures. The energy exchanged here is thrown away. They increase the pressure differential across the turbine and save condensate. There is insufficient cooling medium in steam locmotives.
The high pressure feed heaters are, but the low pressure ones are not.
No and no. Why would I need one at home anyway? They shorten battery life.
Urticaria graphica in my case. For most people it clears up by itself after 3 months or so. In my case it lasts 3 to 9 months, goes, but then returns if my immune system is attacked (common cold, etc.). Main trigger is heat, but only after a virus of some sort. So at the moment, I had a virus in March and since then the heat keeps setting it off. It'll go soon.
SteveW
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