Model research of the energy efficiency of a cogeneration backpressure steam turbine installation

Technical University of Sofia, Department of Thermal Power Engineering and Nuclear Power Engineering, 1000, 8 Kl. Ohridski Blvd, Sofia, Bulgaria

^* Corresponding author: kokhris@gmail.com

Abstract

In the contemporary district heating systems (DHS) heat energy for the customers is generated by cogeneration method, which leads to the saving of primary energy resources compared to the separate production method. The most widespread technology for combined production is based on steam turbine installations with adjustable steam extraction and backpressure steam turbine. In these technologies district heating water is heated to the required temperature either in district heaters in case of steam turbine with adjustable steam extractions or in boiler-condenser in case of backpressure steam turbine installations. The temperature of the district heat water at the inlet of the CHP installation depends on the mode of operation of the DHS. The heat load, distributed to consumers, is regulated at the heat source (CHP installation) by temperature and flow rate of the district heating water, mainly following the change in climatic factors. Current study presents the development of a simulation model of existing CHP backpressure steam turbine. The object studied is a backpressure steam turbine type SST-300 CE2L/V36S. Presented are results from the validation of the simulated model with data from the design documentation. The model has been used to study the energy efficiency of a steam turbine installation based on multivariate simulation calculations. The results obtained relate the energy efficiency indicators of CHP backpressure steam turbine with the factors that characterize the mode of operation of the district heating system.