Abstract: The present system employs a turbine engine system which has three turbo rotor sections coupled to the same drive shaft. The first section employs a high temperature multi-stage expansion turbine to provide the major source of mechanical power. The second section employs a multi-stage turbo compressor which functions to compress air from the ambient, and such compression provides heat, through an interstage heat exchanger, to a heat reservoir, which may be an enclosure which it is desired to heat, or the atmosphere. The third section takes part of the compressed air from said second section and, (after said air is cooled either to near ambient temperature in the cooling mode or near the enclosure temperature in the heating mode) expands that air in a low temperature multi-stage expansion turbine to accomplish three goals. First, the expansion of the compressed air drives the expansion turbine to provide a second source of mechanical power which assists in driving the compressor section.