Abstract: A power conversion system is constructed of a plurality of identical Stirling engine modules paired off in opposed, aligned relation with their respective expansion spaces in juxtaposition. Two engine module pairs are arranged in a common plane and in mutually perpendicular relation to create a module group, with plural such module groups stacked together to provide an expanded, self-balanced system with all the modules sharing a common, centrally located thermal energy source. Each module includes a pair of compression positions operating on a common axis intersecting the displacer cylinder axis at right angles. Heat exchangers, either tubes or heat pipes, are disposed within the expansion space to transfer heat from the source to the working fluid therein, thus providing a more idealized Stirling engine cycle.