On the basis of the research status at home and abroad

a direct supercritical carbon dioxide(S-CO_2)recompression tower solar thermal(SPT) power generation system model was established

and the effects of turbine/main compressor inlet temperature and inlet pressure on each subsystem and the SPT integrated system were analyzed. Based on the orthogonal array

genetic algorithm is utilized to optimize the parameters to obtain the smallest total exergy loss rate of the system. Moreover

the model with the fifth optimization parameters is calculated for the summer solstice day and day time series. The results show that

the best turbine inlet pressure reaches the upper limit of the given range

the best inlet temperature of the turbine is within 784～841 ℃

the best main compressor inlet pressure is within 7.68～10.00 MPa

the best split coefficient is 0.25～0.32. The minimum total exergy loss rate of the system(SPT integrated system) is 70.72%～76.87%

it shows that the optimal cycle low pressure does not necessarily have to be close to the critical pressure

and the optimal cycle high temperature does not necessarily have to be as high as possible. At different times

the total exergy loss rate of the system depends on the exergy loss rate of the heat collection subsystem. At 8:00—11:00 and 16:00—18:00

the heliostat exergy rate has a greater influence on the total exergy loss rate of the system

while at 11:00—15:00

the exergy loss rate of the heat sink has a greater influence. The research results can provide a reliable reference basis for optimization design of S-CO_2 tower solar thermal power generation system.