Solar thermal power plants coupled to supercritical CO2 cycles seems to be a way to increase the global solar-toelectric efficiency. For that, the concentrating solar technology that is best integrated is the molten salt central receiver with a thermal energy storage associated. This work is focused on one of the main challenges of this scheme: the source heat exchanger transferring the thermal energy from the molten salt in the solar field to the CO2 in the power cycle. A new design, based on the printed circuit heat exchanger technology is proposed, that withstands the pressure difference and avoids the molten salt plugging when circulating through microchannels. The thermo-mechanic model of this heat exchanger is also calculated. This work also addresses a thermo-economic optimization of the printed circuit heat exchanger proposed. For that, it is considered the global performance of the solar thermal plant for three layouts: recompression, intercooling and partial-cooling cycles. This optimization yields to a great reduction in the investment cost of these source heat exchangers, achieving the lowest cost in the partial-cooling configuration, followed by the intercooling and finally, the recompression. This trend is also observed in the global performance of the solar plant, so the partial-cooling layout is the one with the lowest levelized cost of electricity; this value is similar to that of the intercooling layout, and both are well below from the cost in the recompression layout, which results the most expensive configuration.