Publicou 8 edições por ano
ISSN Imprimir: 2150-3621
ISSN On-line: 2150-363X
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EXERGY ANALYSIS OF A THERMAL STATION IN A DISTRICT HEATING SYSTEM
RESUMO
This study is concerrned with an energy and exergy analysis of a district heating system that supplies heat in a neighborhood of Bucharest. The system is analyzed for the cold season period, from October to April. The chain of transformation from the fuel energy to the end-use energy is considered, together with associated losses. For this purpose, the system is divided into three main components: production of heat and electricity, district heating network and consumer (buildings). The heat source is a cogeneration plant made up of four internal combustion engines each of which can provide 14.1 MW of electricity and 13.7 MW of heat. A supplementary 12.5 MW of heat is produced in a separate boiler. The energy and exergy analysis was performed for the fuel and the plant main components. The results indicated a mean exergy efficiency of 44% for the engines and 16% for the boiler. The plant overall exergy efficiency of the plant is 37.1%, while its energy efficiency is 87.52%. When the final transformation to the end-use energy (final energy) is considered, the exergy balance of the whole system comes to 32.1%. The importance of cogeneration in incresing the rational use of resources is highlighted, as well as the negative effect on the overall efficiency of decreasing the working fluid temperature.