Dizel motorlu kojenerasyon sistemlerinin ekserjetik ve termoekonomik performans analizi ve optimizasyonu

In this thesis, we perform exergetic and thermoeconomic performance analysis and optimization of diesel engine powered cogeneration systems. The procedure and formulation of thermodynamic and thermoeconomic analysis are provided and they are applied to an actual cogeneration system located in Gaziantep, Turkey [Sanko Diesel Engine Powered Cogeneration (DEPC) plant] with an electrical power of 25.32 MW and a steam mass flow rate of 8100 kg/h. The approach presented in this thesis is an iterative performance improvement procedure in which the integration of the cost and performance data for a given system component permits the calculation of optimum design conditions when the exergy of the component product and the cost of the component fuel based on SPECO approach remain constant. The exergy input to the plant by fuel is 62,800 kW and 40.4% of this exergy is converted to electrical power while steam production accounts for 0.3% of exergy input. The corresponding exergetic efficiency of this cogeneration plant is 40.6%. The exergetic cost rate and the specific unit exergetic cost of the fuel entering the plant are determined to be 1806 $/h and 2.70 $/GJ, respectively. In optimization studies of the plant, the electricity cost and steam cost are determined for three cases. The electricity cost is 8.90 ¢/kWh in actual base case, 6.70 ¢/kWh in thermoeconomically optimal case, and 23.2 ¢/kWh in thermodynamically optimal case. The steam costs are 5.22 ¢/kWh, 4.50 ¢/kWh, and 10.04 ¢/kWh, respectively, in these three cases. Exhaust emission characteristics of DEPC plant are also assessed, and we determined that using combined power and heat production provide fuel savings of 23.8% in energy approach and 17.3% in exergy approach with respect to separate units of power and heat production.Key words: Combined Heat and Power (CHP), Cogeneration, Diesel Engine, Energy, Exergy, Exergoeconomic Analysis, Thermoeconomic Analysis, Optimization