Design and performance study of dry cooling system for 25 MW solar power plant operated with supercritical CO2 cycle

摘要

Dry natural draft cooling towers are mostly employed in thermal power plants in arid areas with no energy consumption and maintenance compared with the mechanical draft cooling system. Different types and shapes of natural draft dry cooling towers (NDDCT) are available in many thermal and nuclear power plant industries. The main purpose of NDDCT is to generate air flow through the finned tube heat exchanger bundles by the influence of buoyancy due to the density difference between the ambient air and the warm air inside the tower. In the present chapter, a one-dimensional MATLAB code is developed to design a NDDCT with detailed specification of finned tube heat exchanger bundles for a 25 MW solar plant operated with supercritical CO2 (sCO(2)) Brayton cycle. The tower height, the tower inlet and outlet diameters and the number of heat exchanger bundles are evaluated after accomplishing the design requirements. The performance study of an air-cooled heat exchanger is performed for a range of sCO(2) inlet temperature from 71 degrees C to 91 degrees C, operating pressure from 7.5 MPa to 9 MPa and ambient air temperature from 20 degrees C to 50 degrees C. The sCO(2) inlet temperature and operating pressure to the heat exchanger significantly affect the cooling system performance. During high ambient temperature period, the cooling potential of NDDCT is significantly reduced.