Numerical Modelling of the Compressible Airflow in a Solar-Waste-Heat Chimney Power Plant

A Solar-Waste-Heat Chimney Power Plant (SWHCPP) is similar to a solar chimney power plant (SCPP) but uses both the solar insolation and the waste heat from industries to heat the working air. To model the variation of the air density due to the high temperature rise, a 3D numerical model, in which the air density is modelled by the ideal gas law, is established for the SWHCPP in this study. Comparing with the conventional CFD model and the experimental benchmarks, the new model can suppress the overestimation in the simulated results and generally indicates an acceptable accuracy in the performance determination of the SWHCPP. In addition, a method of directly integrating the air density profiles captures the right variation in the system performance during the numerical experiment with multiple flue gas injection flow rates and it would be more suitable to be used for the modelling research about the SWHCPP. The simulations indicated that more than 50% higher power output was achieved due to multiple-stage heating with the waste heat while the existence of the waste heat slightly influenced the absorption of solar insolation.