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dan wong
14-06-2001, 06:25 PM
Try to imagine what refrigeration system would be like in the 21st centry. any wild guess?

WebRam
14-06-2001, 07:04 PM
I hear a lot of talk about Magnetic Refrigeration. Any more info on that ?

dan wong
14-06-2001, 09:19 PM
In the desert climate, such as Arizona. We have abundance of static electricity, I am thinking there must be some way to amplify, store, utilize, harness this type of energy for cooling- like the Peltier effect. what do you think? ( I know this type of thinking is kinda wild)

Brian_UK
14-06-2001, 11:29 PM
Originally posted by WebRam
I hear a lot of talk about Magnetic Refrigeration.
Isn't that a clever name for all those little sticky things you can decorate your fridge door with ?:D

dan wong
14-06-2001, 11:57 PM
Since the earth is one giant magnetic field, I wonder if man might be able to harness and capitalize on this by the 21st centry if not sooooner.

dan wong
16-06-2001, 09:09 PM
look at our car battery, it consisit two electrods and some chemical in between.

Now, look at our ocean, it contain what ever chemical we can think of in large quanity, There must be a way mankind can design the proper electrods to capitalize this. What do you think?

dan wong
16-06-2001, 09:28 PM
If people were hypnotise to beleive their surrounding temperature is ok. do they still need air conditioning? what do you think?

Prof Sporlan
19-06-2001, 01:16 AM
A 21st century concept I admire can read about at http://www.keithfranklin.com/

The Prof has had a fascination for thermoacoustic refrigeration, despite the fact it doesn't require a thermostatic expansion valve.... :) Last time he took a look at the subject, prototypes had less than stellar efficiencies, and there were a number of issues left to be resolved with the design of the "sound compressor". No doubt these issues will be addressed.

It may likely go the way of the Stirling engine/cooler, which in theory, is as efficient as the Carnot cycle, but economics destined it to some specialized low temperature applications. An interesting site on this subject: http://www.sesusa.org/

Derek
19-06-2001, 06:01 PM
What no mention of air side....or even vortex tubes. Tut Tut

dan wong
19-06-2001, 07:36 PM
Originally posted by Derek
What no mention of air side....or even vortex tubes. Tut Tut

You took the words right out of my mouth, I was just about to post that thought.

subzero*psia
20-06-2001, 10:43 PM
The earth is a giant magnet surrounded by magnetic fields... each field must be unique in frequency and varying over its entirity from North to South right? Imagine Jupiter's magnetic fields... kinda makes you wonder if it wouldn't be possible to create a huge coil assembly type freak meter... like a huge auto magnet. The ride would be so smooth and fast that you might even get from point A to point B before you left.... Nawww! Can you imagine such a beast though.... it'd be the size of the ship on Independence Day! LOL!! Beam me up Scottie!

:eek:

Prof Sporlan
21-06-2001, 02:37 PM
The ride would be so smooth and fast that you might even get from point A to point B

One could consider drilling a tunnel thru the earth... If we go thru the center of the earth, and our acceleration due to gravity remains reasonably constant at 32.2 ft/s<sup>2</sup>... The Prof recalls the earth is approx 8000 miles in diameter so...

1/2 distance thru the earth = 4000 miles * 5280 ft/mile = 32.2 ft/s<sup>2</sup> * t<sup>2</sup> / 2

t = 1145 sec = 19 min

So it would only take 19 minutes to reach the center of the earth, or 38 minutes to reach the other side. Of course, the tunnel would have to be pulled to a vacuum to eliminate air resistance. If one could eliminate all friction, we would have the added benefit of not requiring any energy to make the trip...

Interestingly, the velocity of our craft would reach:

v = 32.2 * 1145 = 36,869 ft/sec = 25,138 miles/hr

when it reaches the center of the earth.

Those Chunnel workers should be looking for a new project... :)

Brian_UK
21-06-2001, 08:36 PM
Don't you just love it when someone gets all serious on you in the middle of a dream :D

Interesting thought though Prof, with a route to the centre that size I think a few ground source heat pumps might struggle a bit....

dan wong
24-06-2001, 08:55 AM
Professor, If the center of the earth is the center of gravity, once we reached the center, how is it possible to accelerate toward the other end at the same velocity( refering to your post). Once we reach the center wouldn't we declerate toward the other end? wouldn't we oscillate between north and south and eventually come to a stop at the center of gravity?.

If the tunnel was make vaccuum, would we still need heat shield?

A morbit thought, at the center of gravity, wouldn't we shrink to the size of moth ball? uuuuh , bad dream.

Prof Sporlan
25-06-2001, 02:20 PM
I expect we'd actually be somewhat neutralised surrounded by about half the normal gravity but from all directions, we might feel like we're floating in space

The Prof concurs. One would have an essentially weightless experience traveling (falling) thru the center of the earth. It would be 38 minutes of free falling.

Of course, if the tunnel did not go thru the center of the earth, say, the tunnel connected London with New York, the traveler would only experience only partial weightlessness. Interestingly, the 38 minute duration of the trip would still remain constant, regardless of where the tunnel is drilled, as long as the tunnel remains straight.

dan wong
25-06-2001, 07:35 PM
Originally posted by Prof Sporlan


The Prof concurs. One would have an essentially weightless experience traveling (falling) thru the center of the earth. It would be 38 minutes of free falling.

Of course, if the tunnel did not go thru the center of the earth, say, the tunnel connected London with New York, the traveler would only experience only partial weightlessness. Interestingly, the 38 minute duration of the trip would still remain constant, regardless of where the tunnel is drilled, as long as the tunnel remains straight.

I am having problem visualize above concept. If an object is gravitate to the center of the earth. regardless wheather it north, south or any direction, why wouldn't an object stop at the center of gravity? Where is f(x)=0 ?

Prof Sporlan
25-06-2001, 08:32 PM
I am having problem visualize above concept. If an object is gravitate to the center of the earth. regardless wheather it north, south or any direction, why wouldn't an object stop at the center of gravity?

Consider a rock which is dropped from a balloon one mile above the earth's surface. If we assume a constant 32.2 ft/s<sup>2</sup> acceleration due to gravity and negligible air resistance, we can determine the rock will take:

32.2 * t<sup>2</sup> / 2 = 5280 or t = 18.1 seconds

to hit the earth. We know the rock will start its decent with a velocity of zero. Its highest velocity will be when it hits the earth, or:

32.2 * 18.1 = 583 ft/sec or 397 miles per hour.

In reality, air resistance will lengthen the time for the rock to hit the earth, and reduce its velocity when it hits the earth. But the rock will be at its greatest velocity when it hits the earth.

If the rock were to fall into a hole thru the earth, however, the rock would continue increasing in velocity until it reached the center of the earth. It would not be until the rock passes thru the center of the earth before gravity could being slowing it down. If we assume no air resistance, the rock would not come to a stop until it traveled the same distance to reach the center of the earth, i.e., it would reach the other side of the earth, stop, and then fall back in for a return trip.... :)

Somewhere lurks a connection to 21st century refrigeration here.... :)

Gary
25-06-2001, 09:09 PM
The Prof concurs. One would have an essentially weightless experience traveling (falling) thru the center of the earth. It would be 38 minutes of free falling.

Assuming we would be making the trip in an enclosed vehicle, I would expect some small sensation of gravity due to acceleration and decceleration, for most of the journey.


I am having problem visualize above concept. If an object is gravitate to the center of the earth. regardless wheather it north, south or any direction, why wouldn't an object stop at the center of gravity? Where is f(x)=0 ?

Here's an alternative explanation:

Hang a ball from a string. Hold the ball off to the side and drop it. It doesn't stop at the center of gravity (bottom). Momentum carries it past the center and upward on the other side. How far it travels up the other side (ignoring friction) would depend on its speed when it reaches the bottom.

Similarly, if the ball were dropped to the center of the earth, it would gain speed while dropping, and momentum would carry it past the center of gravity and upward toward the other side of the earth.


Somewhere lurks a connection to 21st century refrigeration here....

Seems doubtful, but one never knows where free falling thought may lead... :)

Gary
25-06-2001, 09:44 PM
Imagine our vehicle having a pool of water on top. As it nears the center of the earth, the water boils off, cooling the vehicle and increasing the acceleration, and we end up getting a free ride to China.

Or maybe a quick trip to Mars... :)

subzero*psia
26-06-2001, 03:39 AM
Okay, you guys dig the hole and we'll prove your theories... I'll hold a stop watch and time you when you enter, bounce back, re-enter, bouce back...

My dad loved magnets... and water.... he was always trying to invent the perpetual motion machine. He knew he never would but he never gave up... he just loved to tinker with it. I sure miss the old boy... taught me to pull wire when I was 12... I completely wired my first home from start to finish when I was 16... (I had an aching question in the back of my mind on that job and I thought I would just give it a whirl... nobody had ever told me why or why not sooo...) the inspector said I had done a wonderful job and that I was very consistent... the whole house was wired with reverse polarity! LOL! :D I had to go back after school was out the following weekend and rewire all my switches etc.

Don't really know where that came from other than the thought about perpetual motion, but I thought I would share it with you.

Sawdust
10-04-2002, 06:41 PM
Beam me up Scotty, there is no intelligent life down here :)

dan wong
20-04-2002, 12:30 AM
Originally posted by Sawdust
Beam me up Scotty, there is no intelligent life down here :)

There is plenty of intelligent life here in North America !!!!!! hahaha... just couldn't pass that up.