A combustion unit is burning refused derived fuel (RDF) consisting of 88% organics, 7% water, and 5% inorganics (inerts) at a rate of 1000 kg h. Assume the heat value of the fuel to be 17,000 kJ/kg on a moisture-free basis, and 2,575 kJ/kg is the latent heat of evaporation of water. Assume the facility is refractory lined with no water wall and no heat recovery. Assume that the airflow is 9,000 kg/h and that the under and over-fire air contributes negligible heat. Assume further that 4% of the heat input is lost due to radiation and that 8% of the fuel remains uncombusted in the ash, which exits the combustion chamber at 830 °C. The specific heat of ash is 0.837 kJ/kg/°C, and the specific heat of air is 1.0 kJ/kg/°C. What is the temperature of the stack gases?