Attached is a sketch of a simple Manson cycle engine.  It has a piston (dark grey) running in a conventional cylinder, connected to a con-rod and crank mechanism. On top of the piston is a displacer, which is a stainless steel can to resist the heat from above. It is attached to the piston with a tubular extension.  All the cylinder lubrication is in the lower part of the engine – away from the source of heat.
The piston has ports cut into it which allow the internal gas of the cylinder to vent to atmosphere both at TDC and BDC. This piston is essentially a reciprocating valve controlling the expansion and “suction” phases of the cycle. These engines are very simple to make from scrap car parts and stainless steel cookware – these materials are readily found in any community with a metalworking ability.
They will run on any suitable source of heat. The engine could be turned over so that the hot end sits over a wood stove for example.  An engine of this type could bring the means to generate electricity to Developing communities. It could also be used to pump water, or blow air for a blacksmith’s forge.
The efficiency will only be about 5% or less, but it has none of the complications of steam boilers or requiring refined fuels for its operation. The lower part of the engine can be water cooled by winding a copper tube around the cylinder. The heated water may be used for washing or domestic heating purposes. In the next part I will describe improvements to the basic Manson engine, and how it could be simplified even more.