A new type of concentrating photovoltaic-photothermal solar conversion system with output cogeneration is presented. This technique, called total solar cogeneration (TSC), converts the total solar spectrum directly and cogenerates the output into three energy components: high-temperature heat (HT), photovoltaic electricity (PV), and low-temperature heat (LT). A specially designed heat-mirror with a beam-splitting technique is used to direct a selected portion of the solar spectrum to a HT evacuated-tube receiver. This high-grade heat transfer is optimized, while effectively maintaining the integrity of the photovoltaic conversion efficiency. High-current A.S.E.C. silicon solar cells (nominally 18.3% efficient at 28°C and 35x) are used. An analysis of heat-mirror transmittance profiles has led to an optimized theoretical parametric model profile, that in a TSC system is capable of delivering HT heat with 39% efficiency, while reducing PV efficiency by only 3.4%. In an experimental TSC concentrating module using a dielectric-Au-dielectric multilayer heat-mirror with optical losses, the projected output is HT heat (150°-250°C) at 17.8% efficiency, 12 V d.c. PV electricity at 9.5%, and LT heat (50°-70°C) at 41.9%, with a total cogenerated output efficiency of 69%.