The nineteenth century saw the construction and operation of "fireless locomotives". The engine comprised an integrated and thermally coupled evaporator-absorber; steam passed from the evaporator, through an expander to develop work, and then to an absorber. The heat of solution was employed to drive further evaporation. We have completed the thermodynamic analysis of three cycles that incorporate this process, retaining the original concept of a thermally coupled absorber-evaporator unit. The cycles offer: (1) storage of mechanical energy, (2) storage of heat and later retrieval of heat plus mechanical energy, and (3) continuous conversion of heat into mechanical energy. The expected round trip efficiency of the mechanical energy store was unacceptable (about 40%). The efficiencies of heat-to-work conversion are in the region of 2% less than those of comparable Rankine cycles, accepting and rejecting heat at the same temperature. This rules out the continuous cycle, but the facility of the discontinuous cycle to store heat may render the cycle feasible.
- Honigmann cycle