Global Warming

[gearhead]

Check out the date...http://blog.modernmechanix.com/2006/07/ ... ming-1932/

[terry5732]

Wow , that's a long time to be completely wrong and still not know it. The Earth has warmed less in the last hundred years ( since industrial revoltion ) than it did in the previous era. The Earth's temp went up and down before there were creatures walking upright. And a warmer Earth is not a bad thing. It would be far easier to deal with than an average temp drop of 10 degrees - which could happen anytime and there's nothing humans can do about it.
The sky isn't falling and you couldn't prop it up if it was.

[ken_behrendt]

terry...

From what I've seen, it seems like the consensus of scientific opinion is that the "debate" over the reality of Global Warmins is now over...it's for real!

Those dissident scientists who have opposed the concept have, over the last few decades, become more and more isolated in their opinions and less listened to.

It's been obvious to me that carbon dioxide is, indeed, the major green house gas that is causing this problem and, apparently, the US is emitting about 35% to 40% of the world's output of the CO2 per day with China coming in at about second place.

The solution is simple...we need to stop the continuous 24/7 combustion all of the fossil fuels that power our world and switch to something that will generate power without emitting CO2. Right now, that means either nuclear or solar power. Nuclear power, of course, is a headache when it comes to safely storing all of the radioactive waste it produces and solar power generation is still very inefficient.

To make a successful changeover to non-CO2 emitting power generation is going to require a SERIOUS global committment...something that is going to have to be orchestrated by a body like the United Nations.

I fully expect Global Warming and the solution to it to become the "defining" issue of this century. Fortunately, we still have some time to do something before things really get ugly. I know we will...humans can be very creative and adaptive when they need to be.


ken

[terry5732]

If CO2 was so good at retaining infrared why would ALL window manufacturers use far more expensive gases such as argon for insulation in their double pane windows?
And they take these noble gases that trap heat from our atmosphere and lock them away enclosed in glass !!!
Soon our atmosphere, depleted of these gases, won't be retaining any of the daytime heating at night and we willl all freeze !!!!!!
Take action now and break windows and vacuum tubes !
Free the gas !

[ken_behrendt]

terry...

I'm not an expert of hi-tech windows, but I think their manufacturers are not using the argon gas to block any IR from either leaving the building or entering if from outside. That would be provided by the glass itself which is a very good reflector of IR. The inert gas would serve to block the transmission of thermal energy between the panes of glass. Maybe they use inert gases so that they will not corrode any metal surfaces inside of the window where the gas is contained?


ken

[trevie]

I don't think there is any gas between the glass cavity of windows. I believe there is a vacuum between the panes, this then helps to stop condensation buildup and sound proofing.

[terry5732]

Vacuum can only be used on very small panes as the force will break a larger surface bearing such pressure - 29 pounds per square inch.

Ken - thermal energy is IR, CO2 is much cheaper and won't corrode anything, the noble gases are for insulation. CO2 doesn't insulate - ie stop IR transfer - ie stop thermal energy.

I remember when I was a kid we used to have real hot summers......

[Joel Wright]

In case anyones intrested in the propertys of Co2 click here. http://en.wikipedia.org/wiki/Dry_ice

[ken_behrendt]

terry wrote:

Ken - thermal energy is IR, CO2 is much cheaper and won't corrode anything, the noble gases are for insulation.

By "IR" I mean infrared radiation. This is a form of electromagnetic radiation below the visible in frequency that can be effectively reflected by glass. Thermal energy refers to the actual heat content of a substance and can be measured in various units such as calories.

Whether one uses air, nitrogen, CO2, or an inert gas between the panes of glass, I think the idea is to use it as insulation that will prevent the heat energy of one pane from being transferred to the other pane. They obviously can not use a vacuum to accomplish this, so some transparent material must be used. A trapped gas is the next best thing to a vacuum in this case. However, this gas will not be affected by the IR striking the panes either from the inside of the building or from the outside, because the glass will reflect the IR away from the gas.


ken

[jim_mich]

IR ... Infrared Radiation is NOT reflected by glass anymore then visible light is reflected! We witness it all the time when the sun shines in and we feel the warmth or when we stand in front of a window in winter and feel the cold. Infrared heating lamps pass infrared radiation to heat your McDonald's hambuger.

[terry5732]

I'm sure on Ken's planet the heat lamps have open filaments and no glass.

[ken_behrendt]

terry...

Actually, that is exactly the kind of heat lamp I had as a kid to warm me on chilly winter nights! They are large parabolic metal dishes with an open coil of nichrome wire at the focal point. The only thing that would keep a kid from touching the red hot electrically heated nichrome was a metal cage over the face of the dish. There were no automatic shutdown switches in the event that the thing fell over while a person slept and it heated some combustible material up until his bedroom became "fully" involved. I sometimes wonder how I survived childhood!

Anyway, I was not trying to give the impression that IR could not pass through glass and was totally reflected by it. No...quite the contrary. Exactly how much IR or any other form of electromagnetic radiation is reflected, absorbed, or transmitted by a particular material can depend upon a wide variety of factors such as angle of incidence of the radiation, type of material, contaminants in the material, coatings on the material, etc.

There is special glass used for office building windows that will reflect vitually all of the IR hitting it and then there is the kind of glass used in greenhouses that will allow most of the IR striking it pass through to then heat the plants and soil inside so that the air temperature will rise as it is warmed by the items as they absorb the IR and experience an increase in their thermal energies.

And, of course, heat lamps with sealed, evacuated envelopes containing a filament must be constructed of a special glass that will allow the IR to escape so that the bulb's temperature will not rise to the point where it can damage the lamp.

As far as double pane "hi-tech" windows are concerned, I think that the main purpose of the inert gases sealed between the panes is to slow the passage of thermal energy from one side of the window to the other. Most likely, the inside pane is designed to reflect IR back into a room while the outside pane also reflects IR back into the outside. However, some of the incident IR will be absorbed by the glass and converted to heat and the gas must somehow dampen the transfer of this heat energy from on pane to the other.


ken

[ovyyus]

http://en.wikipedia.org/wiki/Insulated_glass

Insulated glazing is a piece of glazing consisting of two or more layers of glazing separated by a spacer along the edge and sealed to create a dead air space or a vacuum between the layers. When it is made of glass it is called insulated glass.

Insulating windows are usually double paned, but windows with triple panes or more are sometimes seen in very cold areas. Insulated glazing is mounted in a sash or frame as if it were a very thick piece of glass.

The dead air space between the layers of glass may be filled with air but an inert gas like argon provides better insulating performance. Argon (Ar) has an atomic mass of 39.9, which is much more than nitrogen (N2) and oxygen (O2) molecules, which have a molecular mass of 28.0 and 32.0 respectively. As a result, argon atoms move significantly slower than nitrogen and oxygen molecules at the same temperature. This reduces convection and decreases the energy transfer between one side of the glass and the other. Typically the spacer is filled with desiccant to prevent condensation and improve insulating performance. Less commonly, the air is removed, leaving a vacuum, which has no convection at all. This is called evacuated glazing.

Often the insulating quality is used in reference to heat flow where the gap between glazed sheets is optimum at about one centimetre. A larger gap allows for convection currents and negates the dead air space. However, in some situations the insulation is in reference to noise mitigation. In these circumstances a large gap improves the noise insulation quality or Sound transmission class.

Insulated glass may not be cut to size in the field like plate glass but must be manufactured to the proper size in a shop equipped with special equipment.

[ken_behrendt]

Bill...

Thanks for that excellent information on hi-tech window design. It seems that argon gas is preferred because, being its atoms are about 30% more massive than either oxygen or carbon dioxide, they will, at the same temperature, be moving much slower than those two lighter gases' atoms. This, of course, will slow the rate of heat energy dissipation through the double paned windows.

Seems the days of just putting a simple pane of thin glass in a window frame are over. Now that we're trying to be as energy conservative as possible, the cost of a window has escalated.

I predict that, in the future, houses and buildings will no longer have windows. We'll view the exteriors of our homes and building via 3D, high resolution holographic monitor screens! That way, the amount of heat energy transfered through the walls of any building can be minimized and energy costs dropped even further.


ken

[racer270]

my 2 cents,........ the gas leaks out over time.
i don't know how long it takes , and i don't think anyone is checking either .