Düzce Üniversitesi Bilim ve Teknoloji Dergisi (Jan 2020)
Exergoeconomic Analysis of an Industrial Cogeneration Cooling System Powered By Natural Gas Fueled Diesel Engine
Abstract
This study presents the exergy and exergoeconomic analysis of a natural gas-powered diesel cogeneration system. The cogeneration system is designed for a sports complex with 1000 m2 closed area in Afyonkarahisar city. Natural gas is used as the fuel in the cogeneration system of the sports complex, which includes a swimming pool and ice rink. The natural gas diesel engine is used as the primary energy source for the cogeneration system. In the system, the electricity required for the cooling cycle is produced from the natural gas diesel engine. At the same time, the engine exhaust gases are used in the process of heat generation for swimming pool water heating. Finally, the waste heat discharged from the system is used to produce electricity in the thermoelectric power unit. The cogeneration system was modeled thermodynamically by the EES program on a computer and then economically analyzed by using the Aspen Plus program. The operation of the cogeneration system is described in detail, and a methodology based on exergoeconomic relations and SPECO method is provided to allocate cost flows through subcomponents of the system. The results were compared by using thermodynamic and exergoeconomic performance parameters. The exergetic efficiency of the cogeneration system is found to be 28.74%, which indicates that 71.26% of the total exergy input to the system, mainly by natural gas, is destroyed. As a result of the economic analysis of the cogeneration system, the investment cost was calculated as 62,000 $. The exergetic cost rate and the specific unit exergetic cost of the power produced in the cogeneration system are calculated to be 0.75 $/h and 10.93 $/GJ (0.039 $/kWh), respectively. The specific unit exergetic cost of the energy produced in the cogeneration system for cooling the ice rink and heating the swimming pool in the sports complex are calculated to be 6.152 $/GJ (0.022 $/kWh) and 4.221 $/GJ (0.0152 $ /kWh), respectively.
Keywords
