Thread: 'IT' info...
View Single Post
  #12   Spotlight this post!  
Unread 24-06-2002, 01:58
archiver archiver is offline
Forum Archival System
#0047 (ChiefDelphi)
 
Join Date: May 2001
Location: Pontiac, MI
Posts: 21,214
archiver has a reputation beyond reputearchiver has a reputation beyond reputearchiver has a reputation beyond reputearchiver has a reputation beyond reputearchiver has a reputation beyond reputearchiver has a reputation beyond reputearchiver has a reputation beyond reputearchiver has a reputation beyond reputearchiver has a reputation beyond reputearchiver has a reputation beyond reputearchiver has a reputation beyond repute
You Go, Patrick

Posted by Dodd Stacy at 03/09/2001 1:21 AM EST


Engineer on team #95, Lebanon Robotics Team, from Lebanon High School and CRREL/CREARE.


In Reply to: Re: Sterling Engine
Posted by Patrick Dingle on 03/08/2001 11:04 PM EST:



I'm just back from travel, and here Patrick, Chris H, and Joe are discussing my favorite stuff: heat engines, Stirlings (Sterlings), global warming, and politics and technology. And I'll start by saying Patrick is closest to the mark by my way of seeing and understanding the world and thermodynamics. I was going to try to take off on specific aspects of the various posts, but I decided to just spout and let the previous posters relate my stuff to theirs as they care to.

First, global warming. Come on gentlemen, engineers and scientists extrapolate past trends forward in time and examine the implications. The history of atmospheric CO2 concentration over several hundred years, as measured from the Greenland ice cores, shows an uncanny correlation to the history of human consumption (combustion) of fossil fuels as our population grew and our technology advances brought on the Industrial Age and the modern age. This history shows two things that are cause for thought. First, the CO2 concentration varies exponentiontially with time, just like human population, wealth, and resource consumption (energy, autos, gasolene, etc.). Second, this clearly human-correlated pattern has resulted in an atmospheric CO2 concentration more than 10% increased over the historic background level, when we were just pipsqueaks on the planet.

You don't have to be a rocket scientist to wonder how this might play out, even if various parties want to focus on the details of where temperatures are presently measured, how long they've been measured, etc. The earth is a still-cooling piece of real estate with a molten rocky inside, that stuff that comes out in volcanic erutptions. It is also toasted by incoming radiation from our nearby significant (thank goodness for Sol) star, the sun. Also, thank goodness, it's surrounded by space at about nothing for temperature, so we can radiate away the solar heat we receive and the heat conducting out to the surface from the cooling planet core (hmm, think long term on that, but it's been going on a few billion years so far). Oh yeah, and also we have to radiate away from the planet the heat we release from converting STORED ENERGY (like fossil fuels) to useful forms like electricity, transportation, GINGER, HVAC, etc.

Punchline? All of these various sources of energy which wind up getting dumped at the surface of the planet as heat have to radiate off to deep cool space through the atmosphere. Our engineering understanding of the performance of the atmosphere, including its clouds, at transmitting the heat radiating out from the surface of the planet and at transmitting or reflecting the energy arriving from the sun is sophisticated but incomplete. But if we know that we have already increased the atmospheric CO2 by 10%, that we continue to increase CO2 in an exponential fashion with our present technology and population trends, and that CO2 has properties for transmitting and reflecting radiated heat in the applicable wavelengths that are different from the properties of the presently constituted atmosphere, what would we infer from all of that if we considered it without a pre-existing attitude or agenda? I'm not up to a heat transfer tutorial (and you're probably not either), but when we change the heat transmitting/reflecting characteristics of a layer of stuff perpendicular to the direction of heat flow in a system like our planet, the result is that the temperature adjacent to the changed layer readjusts. Put storm windows on your house, and the temperature on the inside surface of your original window rises. And if you want to be in denial about any of this, just sit back and wait for that exponential behavior to double the CO2, quadruple it, etc. Oh, who cares, we've had ours and we're dead and gone. To hell with our descendents - literally.

This rant so far only looks at changing the heat transfer capabilities of the atmosphere because of changing the CO2 concentration. It gets worse. We keep increasing the AMOUNT of heat we must radiate away through the atmosphere as we raise our global standard of living (energy consumption) and increase our population. That ALSO will make the surface temperature rise. I don't care if you don't think you can measure it yet. Wait till those 1 billion people in China discover the joys of SUV's. And the soon to be 1 billion people in India all get electric lights and refrigerators in their homes. (Or did you think the rest of the world already lives like we do?)

Here's the deal: virtually ALL the energy we use, not to mention the energy we sacrifice to inevitable inefficiency in heat engines when converting chemical, nuclear, of solar energy into the more convenient forms for use (electricity, light, etc), it ALL winds up as heat on the planet surface and lower atmosphere when we're done with it. More people, higher living standard, more heat to radiate away, hotter planet. There is a very fine ASME paper from maybe 10 years that quantified the answer to this question: "If all the people currently living on the planet increased their standard of living (per capita energy consumption) to that of the average resident of the US today, and if that energy was supplied by STORED ENERGY forms (fossil, nuclear, etc.), how many degrees would the surface temperature of the planet rise to enable rejection of the increased heat load?" I don't recall the exact answer - it was a goodly number of degrees - but the calculable implication was massive planet wide relocation of populations away from flooded coastal areas.

And that's just for the rest of the people on the planet to catch up with us now. Unless we feel comfortable with our privaledged position in the world AND expect the other peoples to never experience it, we better get busy with better technology. And by the way, to end this rant, the free market does not cause this better technology to be developed and adopted. Individual inventors can't do it. Noble, advanced, sophisticated societies do it through the wise and enlightened actions of the governments they choose. We need now to make the new technologies because they are hard. How will we do that?

Dodd

ps. Not to be gloomy. There is an answer that can leave a habitable world for our distant descendents. Look at some of the capitalized words above for a clue.


__________________
This message was archived from an earlier forum system. Some information may have been left out. Start new discussion in the current forums, and refer back to these threads when necessary.