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 49000 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.

The feasibility of wastewater treatment sludge from the power plant was studied as cement substituted material. The sludge were used as the air dried sample and the oven dried sludge at 300o C. Their properties then the optimum ratio of cement substituted portion for cement block were determined. In the control set; cement sand and water ratio were 1 2.75 and 0.825 (w/w) respectively while the treatment set sludge replacing were varied at 10 20 and 30 %. The blocks were produced and cured in tap water for 7 14 and 28 days and tested their compressive strength. The leaching ability of heavy metals namely Cd Cr Cu and Pb were determined by Waste Extraction Test or WET (according to the standard from the Notification of Ministry of Industry A.D. 2005) and Toxicity Characteristic Leaching Procedure; TCLP (US EPA method 1311). The results showed that the solution from cement block curing both of control set treatment block had basicidic pH range 11 – 12 and caused reduction of the heavy metal solubility. The solution conductivity range 5 - 7 mS/cm. The 10% dried sludge cement blocks were the suitable ratio compared with the control set which the maximum compressive strength at 28th day was 253.81 Kg/cm2 and 4.73 % moisture. All metal leaching abilities were less than those Notification and US EPA standard. Those optimum ratios 10 % can be applied to produce cement pot.