Simulation of a 500 kW sloped solar chimney power plant powered by industrial waste heat

Abstract

The solar chimney power plant (SCPP) has been proposed as a promising alternative power plant. According to the literature, the chimney for commercial-scale SCPPs should be about 1 km high. The construction of these tall chimneys is very challenging and the construction cost is enormous. The sloped solar chimney power plant (SSCPP) is a variation of the SCPP. One of the SSCPP’s prominent feature is that its collector is sloped, and then its chimney can be shorter than that of the SCPP. This leads to a lower investment cost of SSCPPs compared with that of SCPPs. Also, previous studies show that the industrial waste heat potential of Thailand is considerable and should be investigated. As a result, this study developed a mathematical model for designing a sloped solar chimney power plant powered by industrial waste heat (SSCPP-WH). The model was justified by validation using experimental data. Then several SSCPPs with different geometrical dimensions were simulated to determine a proper dimension that has the lowest levelized cost of electricity (LCOE). It was found that the LCOE is about 0.14 USD/kWh, the payback period is about 11 years, system efficiency of 1.3% and collector efficiency of 36%. for an SSCPP-WH with a collector area of 49,000 m2, chimney height of 45m, flow area ratio between solar collector inlet and solar collector outlet (AR12) of 14 and waste heat of 10 MW. It was also found that the payback period of SSCPP with no supplied waste heat is lower than that of some SSCPP-WHs. To make sure that the payback period for the SSCPP-WH is faster than that of SSCPP with no waste heat, a ratio of the supplied waste heat to the absorbed solar energy of the SSCPP-WH must be greater than 0.34.