Criteria for Thermal Efficiency of Combined Heat and Power and Nuclear Power Plants Generating Electrical and Thermal Energy

Combined heat and power generation is the most efficient way to use fuel heat. The differential production of a combined power plant using organic fuel leads to the problem of determining the criteria for its thermal efficiency. Currently, specific reference fuel consumption (SRFC) for the supply of electrical and thermal energy is used in terms of these criteria. These characteristics are determined by the conditional division of the total fuel consumption for a combined heat and power plant (CHPP) into electrical and thermal energy. Although the division methods have been discussed in Russian literature for over 70 years, thermal efficiency should be determined based on the analysis of the actual operating modes of CHPP equipment in the energy system. Due to the design features of Russian T and PT turbines, the generation of electrical energy in a condensation cycle of a CHPP leads to a decrease in the energy efficiency of the latter. As a result, it is recommended to use the fuel heat utilization coefficient and the specific production of electrical energy based on the heat consumption as CHPP thermal efficiency indicators. In contrast to CHPPs using organic fuel, at nuclear power plants (NPPs), thermal energy is provided by unregulated turbine extractions. The significantly lower cost of reactor thermal energy and NPP operating characteristics results in a method for analyzing the thermal efficiency of NPPs, which is different from that of CHPPs. Since, for economic reasons, it is advisable to operate an NPP at a maximum thermal capacity of the reactor, the energy criterion for the supply of thermal energy is the specific underproduction of electrical capacity. In order to generally characterize the thermal efficiency of NPP operation, it is recommended to reduce the NPP operation indicators to the condensation mode.