Liquid Air Engine

[Boston]

Originally Posted by RonL

OK Boston, I'll give it another shot.
First, I switched horses and I was concerned about changing liquid type, I brought that up and Brian said basically "why not". I kept a little in line to the thread, by supplying information about Liquid Air and how this can be produced on a small scale for small application. there are a vast number of ways to accumulate and apply large amounts of power in short time frames that can produce a product of this nature.
I expressed my reasons for not using Liquid Air or Nitrogen as motor activation methods.
Hence I proposed a system based on using propane liquid and gas, that are in containment and re-circulation on a continual basis, never needing to be replenished. A one time purchase. I have made a few comments that reflected a change of design and agree some might have lost sight of my thoughts. So I will try to stay on the same thing start to finish.

So here goes.

First thing, lets use a 500 gallon propane tank, just as example....we put 50 gallons in the tank, pay the price for that liquid. It will stay in the tank forever if the valve is not opened.....for general opinion most would agree it is stupid, when I paint the tank flat black and have it in full sun, I'm sure you have some idea what pressure will develop....I am confident to declare 130* F here in Texas, might be close to accurate, which will give a pressure build up in the tank close to 257 psi.
What volume is still liquid and how much gas in the larger space ? now just to make a point.....we install a regulator set to 100 psi, we connect a long hose to some air tool with some spark-less load (make this a remote location and safe distance from anything) we are going to waste some gas here to prove a point.
Open the tank valve and that air tool will perform as well as if compressed air is being used. Load and size of the tool will govern how long the tank will supply a working volume of pressurized gas, the tank will get colder, quicker than an air system (but that comes much later) you can calculate just how much energy was transformed into work, this was just from what came from sunshine heat.

And therein lies your first basic error. Your refusing to consider the energy required to compress whatever gas you have expanding regardless of its thermal characteristics at the time of the phase change.

The system I have tried to describe, takes this entire action inside a sealed tank where no propane is moved outside the sealed tank, that will come later when more thermal absorbing area is needed.

How to set up the discharge of high pressure gas volume, into something that can accept it which is also inside that same tank, is simply a certain volume coiled pipe that has one or more expander plumed into that coil. As I mentioned 30 cubic feet of volume is a comfortable fit and still leave room for all the supporting equipment. This pipe will need a pressure relief valve ( assume 100 psi down to 50 psi working range) at the high pressure inlet and a low pressure check valve at the lower end. (flapper or ball ) Anytime the low pressure end exceeds tank pressure by even the slightest amount, there will be a discharge back into the tank liquid.


Ok so now your expending energy to artificially maintain a low pressure area inside the tank or are expending energy to re-compress the a vapor to a fluid. Either way your spending energy.

When the tank is filled to whatever quantity is designed for the system, the initial pressure will be low or zero. The pressure and check valves will seal the coiled pipe, keeping it's pressure low, as the pressure increases in the main tank, this buildup of pressure is free as it is solar thermal heating.

again fundamentally wrong, any left over volume in the tank will be filled with vapor until the pressure equalizes with the fluid. If you'd ever worked with liquid nitrogen you'd have noticed it "steams" off until its all gone. If you'd contained that liquid nitrogen in a bottle that "steam" would stop once equilibrium was reached.

For a really slow cycle, let the sun warm the tank and when 100 psi is reached the pressure will release through the relief valve, and will start flowing through the expansion motor(s) this work is used in some form (designer choice) the gas exhausted will be cooler and expanded in direct relation to that work performance. The exhaust from that unit will still possess some energy that performs work through another expander and through as many as needed to extract as much energy as possible.

The last unit in series actually becomes a compression unit (design size will vary), it draws it power from the same shaft that received work from all the previous units. At this point the gas will be expanded to a large amount and depleted of heat based on previous work of the expander units. If a large portion of the coiled pipe is submerged in tank liquid and if tank pressure has fallen to 50 psi, the liquid temperature should be close to 30* F, at this point any condensed liquid in the pipe will be pushed out into the main tank.

A portion of work should be in rotation of a heavy flywheel and will, if needed, be used in this compression process.

At this point the system will be basically depleted and start a somewhat slow pressure buildup for another cycle. There should be residual heat in the rotating equipment, due to friction and will move in accordance to internal temperatures, other division of that first cycle energy burst, would likely be split by some amount into, flywheel rotation, some electrical quantity to battery storage and some to the compression of the cooler expanded gas.

All this is a free running cycle based on thermal heating from the sun, not very useful in comparison to setup cost of the system. Setting it in the ocean water and using more internal propane liquid, will produce quicker cycles at a little lower pressures (?) but they happen 24 hours a day.

Increasing temperature delta using electric generated heat and flywheel assisted expansion of gas, would allow the used of heat exchangers to absorb more thermal energy from the waters a boat is floating in. This is also where storage of hot and cold quantities of antifreeze liquid can lever the magnitude of cycle strength. Electric can only create a larger delta, but storage can be any amount based on mass of flywheels and liquids, along with battery supplying power to mostly utilities and maybe some additional motor power.

The design requirements can be as varied as shoe sizes and shapes, so this should bare testimony to why an old man on retirement income might be shy to tackle a job that even though clear in the mind, is far beyond calculation ability.

All things in motion at the same time, every pressure and temperature in a constant change of measurement as speeds increase or decrease, the magnitude of adjustment factors is overwhelming, the most solid and dependable factor is that of balance between heat absorbed and work dispensed in application or storage.

Energy and heat can be wasted, but only after it is moved out of the tank system.
The simplest thing I can say, is that a tank completely sealed and all energy transferring, mechanical and electrical rotating parts are inside the cold sink.

The best I can do until I try again.

RonL

I'm not going through the whole thing but you've got a ton of holes in your basic understanding of how this stuff works

[RonL]

Originally Posted by Boston

I'm not going through the whole thing but you've got a ton of holes in your basic understanding of how this stuff works

I'm going to have to call it quite for now, a full day tomorrow and tomorrow night, I'll find time to consider your's and gonzo's comments.

I made mention of temperature range from -44* F up to 130* F
Pressures from 0 psig up to 257 psig, Boyles law seems to rely on constant values. I'm not good with the books, but I base a lot on my work and observations when using all these things to disperse energy, not the conservation or collecting and transformation of it.

Thanks and good night for now.
Best wishes

RonL

[Boston]

That pressure of 0 psi up to 257 psi is the energy your not getting your head around. I'm all for green, hell Im kinda the resident screaming environmentalist but your liquid air engine just doesn't fly. Oh there might be a liquid air engine that runs, but its energy budget is all kinds of screwed up.

[RonL]

Originally Posted by Boston

That pressure of 0 psi up to 257 psi is the energy your not getting your head around. I'm all for green, hell Im kinda the resident screaming environmentalist but your liquid air engine just doesn't fly. Oh there might be a liquid air engine that runs, but its energy budget is all kinds of screwed up.

Good morning Boston,

That is at least one thing I do fully understand. If one should put good insulation around the tank, open the valve to release any pressure, the results will be a 0 psig condition and -44* F.
Close the valve and take off the insulation, place the tank in a large body of 130* F liquid, of some kind, a gauge will climb to 257 psig @ 130* F, the time that it takes for this to happen will be completely dependent on the proprieties of the tank that holds the propane.

The factors of manipulation in how to increase or decrease this time of thermal transfer, are so many I lose track of how to decide what design to focus on.

Before I went to sleep last night (a very short time) I thought of two things.
1. The laws of physics and thermodynamics work, regardless of what I understand or know how to calculate.
I might decide to throw together something like a raft, if I know the basics of things that float, I only need to know a little book stuff if I wanted to have some idea of how it is going to set in the water, before I push it in,Right ?

2. I have for now, made my best effort to try and give some kind of description about things I know and how they work in my hands and expect them to work the same basic way in my design.

The mechanics work, regardless of me being able to understand or calculate (other than some very basic values) That is only a requirement needed in order to convey the vision of my mind and the magnitude of how well it might perform.

The very minimum explanation I can think of, is simply this,

***(an intertwined assembly of a, Heat Pump, Refrigerator and Stirling Engine in a single package )***

If one can understand a Stirling Engine driven by an electric heat element the rest should fall in place.

If one cannot understand the path of heat transfer in all these proven machines and how the heat rejection or absorption of any one has an affect on another, then my lack of formal education is the limit of communication between anyone I try to make my explanation to.

The sum of control for every thing, is Conduction surface area, insulation, energy conversion and storage. So many ways to use these three things, along with the induction of heat from sources outside the main tank, if one should want or need to extend the magnitude of performance.

RonL

[Boston]

the part your missing is that its not just the pressure that changes, the amount of liquid in the tank has been reduced as well in order to phase change enough material to raise that pressure back to equilibrium. So in fact you are still just using the stored energy in the compressed liquid to "power" the increase in pressure. Any way you slice it, its not free energy

[RonL]

Originally Posted by Boston

the part your missing is that its not just the pressure that changes, the amount of liquid in the tank has been reduced as well in order to phase change enough material to raise that pressure back to equilibrium. So in fact you are still just using the stored energy in the compressed liquid to "power" the increase in pressure. Any way you slice it, its not free energy

I have lost two post's and do not have any more time for now, I'll get back in a day or two.
I'll do my best to be direct to each of you comments.

I will be able to look in quickly, but not make comments.

Later

RonL