Heat Conducting Liquids
You may sometimes need to refer to the Heat Engine Structure Diagram together with the Vapor Pressure of Natural Gasses diagram in this text when you read certain parts of the SHE description.
In order to construct the SHE in any form, an heat collecting chain that is made up of 1 or more linked sections, as shown in the SHE Structure Diagram, is required.
For the vehicle application to be described in other parts of the text, 3 heat collecting and amplification stages are used.
For low power vehicles 2 heat collecting and amplification stages can be used.
Each of those stages will use a different heat conducting liquid.
In order to have stable year round reference conditions, it is assumed here that the SHE will be operated somewhere in and around the tropic of cancer and the tropic of Capricorn. Other parts of the world may require the liquids to be changed at different times of the year or use a 4 stage heat amplification chain.
That means that the lowest expected air temperature will be about 18°C.
The lowest expected water temperature is between 12°C and 15°C. R134a refrigerant is said to be a mixture of propane and butane.
Selecting suitable heat collectors will be a feat in of itself. The following two points are of relevance for different reasons.
Firstly: The boiling points of the liquid used in each of the heat collection stages must exhibit a reasonable difference in their boiling points, which then allows the collection and amplification of heat through heat conductor expansion and compression.
Secondly: Those liquids should have as low a atmospheric retention time as possible, just in case too much of it starts escaping into the atmosphere. That means that the substances will degrade from an original toxic or none toxic state into to molecular parts that look for new heat in order to join up again with other molecules. As far as material selection is concerned, where possible, none toxic and low toxicity substances are selected, before others.
In the diagram, note the atmospheric retention times of n-butane and n-pentane.
Data about atmospheric retention times of high temperature heat collectors is not available, but it would not be a problem to find a suitable alcohol for the last stage in this design specification.
Even steam could be used as an heat collector and amplifier in the last stage of the heat collection chain, even though all descriptions, past and present, refer to it as a turbine propellant. Note that according to the diagram, it can still be used as a propellant, because it's expansion curve falls between n-pentane and n-heptane types.
A driver fluid that utilizes the collected heat and works as a driver gas for the a turbine electric current generator combination near the output of the system will be required.
The driver gas can be from a mixture of the heat collecting liquids used in the last two stages of the heat collection chain or an alcohol whose boiling point fits suitably between them.
From the diagram, it can be assumed that the driver liquid will produce useful turbine drive power somewhere between 5 bar and 15 bar and it's boiling point will lie somewhere between the boiling points of the last two heat collecting liquids.
1bar = 1.01972kg/cm²
Increase the area of an outlet/inlet and get more power.
Examples of heat conducting liquids for the Solar Heat Engine