No Solid Moving Parts Nearly Reversible Heat Engine

The No solid Moving Parts nearly Reversible Heat Engine idea discussion has led to a few proposed designs.

Of course, solid valves and similar parts do not count as "moving parts" because the amount of force involved in moving them does not increase much as the power of the machine increases, and friction losses there cannot possibly be significant.

These designs share some common ideas:
 * Use of a liquid piston to transmit force
 * Storage of energy in either gas pressure, or a column of liquid

The designs vary in details:
 * What drives the liquid piston to compress gas
 * Expanding gas
 * Descending liquid
 * What stores work done by liquid piston driven by expanding gas
 * Compressing gas
 * Rising liquid
 * Type of heat reservoir
 * Hot and cold separated in space but present at same time
 * Hot and cold present at the same place but at different times
 * The thermodynamic cycle
 * Isothermal compression and expansion
 * Isochoric (isometric) heating and cooling: Carnot cycle
 * Isobaric heating and cooling with CCHEX: Second Ericsson cycle

The designs are discussed on these pages:
 * Pumped storage output multiple expansion tanks few reservoirs
 * Compressed air output single expansion tank multiple storage silos
 * Compressed air is like the stock market: buy low sell high
 * Ericsson cycle engine where nothing big and solid moves