Hello Aqueous Id,
My appologies to any misconception. I was speaking on using the forces of gas to proppel a turbine. Though I am familiar with the working of "Einstein" Ammonia fridge.
"Einstein" who brought us the Ammonia fridge did not incorporate a pump in the form of piston or turbine. The pump so known in the Ammonia fridge is the heating of water causing it move uphill where the Ammonia gas escapes the water and the water falls back down.
It was a useful device to folks who had no electricity. And it demonstrated the work advantage of the hygroscopic absorption of ammonia by water. There are several types of ammonia refrigerators. I was speaking of the type commonly used in homes, which uses a pump. This has a useful and practical advantage over the alternatives. Except for the ammonia, which is harmful, the use of the pump gave folks a sense of security. It's safer than a compressor which has a capacity to explode, and ammonia was considered safer than flammable and explosive gases which were known to have practical use as refrigerants.
Gas does not have to return to liquid to obtain a pressure difference!
We were talking about refrigeration, in which the step change in volume, at phase change, is exploited and used as a mechanical advantage--in this case, a volumetric advantage.
Absolutely no need whatsoever that CO2 be condensed to liquid to obtain drive forces.
The need is to exploit the advantage of the step change in volume at phase change.
A pump and compressor be one and the same, the words pump and compressor are often used to signify which is to be pumped water or gas. Simple experiment pour water into the air intake of a compressor note the pump action to the water.
There is a difference in efficiency. Pumping a liquid moves more molecules per second than pumping a gas, for the same expenditure of torque.
The reason why I post the CO2 phase graph is to show what forces exist between the low temperature and high temperature. In the Case of CO2 it is Dry-Ice at minus 40*C, it has zero gas pressure. At minus 39* C it goes direct to gas with a pressure force of 1 bar. At 30*C it has a pressure force of 60 bar. At 100*C it has in excess of 7,000 bar pressure force. A heat differential of 70* C delivering 6,940 bar of force. Sream at 100*C has 1 bar pressure, at 550*C it has 175 bar pressure. A heat differential of 450*C to acheive 175 bar of force. (Steam phase graph too large to copy and paste, though easily obtained by web search)
Now take your graph and figure out how much energy it takes to compress the gas to its solid phase and you'll understand why ammonia is better. All that energy you spent running your compressor is done for free in ammonia simply by its free phase change from gas to liquid, upon hygroscopic absorption by water.
Check out the magic of hygroscopic absorption.
[video=youtube;-z4liRirdv0]http://www.youtube.com/watch?v=-z4liRirdv0[/video]
This is the advantage that made the Einstein refrigerator useful. (He didn't invent the principle, by the way, although he showed prowess in patent law by filing it. I think the prize for innovation goes to Ferdinand Carre who discovered the ammonia absoption refrigeration cycle in the mid-1880s.) Check out the
icyball, a device Einstein probably had on hand to inspire him.
But back to pressure: compare the 7,000 atmospheres of your machine to the detonation potential of a stick of dynamite and you will begin to see the practical disadvantages.
To obtain a gas drive at ambient temperature the gas must be cooled to lower than ambient temperature.
Which costs energy. This is why there is no such thing as free exploitation of a single ambient temperature. Free exploit of two temps is another thing, which is what gives geothermal its appeal. The point for cranks to recognize that there is no free exploit of a single temperature. It's only free if you have a free temperature
difference, in other words, you need two free temperature supplies.
To obtain a gas drive at temperature higher than ambient temperature heat must be added then later cooled back to ambient temperature.
All of that costs money, and may or may not have any advantage. You have to address design at the system level to ascertain the overall cost to benefit ratio.
You may find the odd behaviour of CO2 interesting. At gas it behaves as a liquid. It begins as Dry-Ice and goes straight to gas when heated. Further heating turns it to liquid. Further heating turns it to gas. Further heating (above 35*C) turns it to Dry-Ice. (note in attached phase graph to original posting, that appearing as solid is in fact Dry-Ice)
At sufficient pressure, water can exist as warm ice, as can many other substances. You need to address the impracticality of operating at 7,000 atmospheres. Compare this to the damage done by an exploding tire, inflated to only 2 atmospheres. I think this is where you are losing folks.
Its a missconception to beleive energy providers shall allways go for the least expensive.
I was actually talking about A/C and refrigeration manufacturers, and end users, who gravitate to the cheapest operating cost, the lowest investment, and the safest and lowest maintenance systems available. By the way, check out dry ice manufacturers. I'm quite certain they use ammonia based refrigeration.
Switching from Steam to CO2 wipes out all need to burn Coal yet more Coal mines are coming into operation.
These are two independent sides of the system. The choice of a fuel to produce heat has nothing to do with the choice of the fluid used to convert heat to torque.
If you want to boil something into a gas force force water is last place you look.
Water is used for many reasons. The fact that it comes to us compressed as a liquid at 1 bar, that it's safe, cheap, easily stored and transported, etc. are all practical considerations you are overlooking. It has a useful 22:1 volumetric advantage at 1 bar, 100 °C.
"fount" .
