Low temperature engine system

An improved engine system is provided which includes a synthetic low temperature sink that is developed in conjunction with an absorbtion-refrigeration subsystem (23) having inputs from an external low-grade heat energy supply (21) and from an external source of cooling fluid (24). A low temperature engine is included which has a high temperature end (22) that is in heat exchange communication with the external heat energy source (21) and a low temperature end (36) in heat exchange communication with the synthetic sink provided by the absorbtion-refrigeration subsystem (23). By this invention, it is possible to vary the sink temperature as desired, including temperatures that are lower than ambient temperatures such as that of the external cooling source. This feature enables the use of an external heat input source that is of a very low grade because an advantageously low heat sink temperature can be selected.