NUMERICAL STUDY OF THERMAL SCHEMES OF THERMAL POWER PLANTS FULFILLED WITH THE АID OF THEIR TOPOLOGICAL MODELS

Further improvement of natural gas usage in power industry is associated with transition to the combined-cycle gas technology, primarily at combined heat and power plants (CHP). Renovation of technology of conversion of fuel energy into heat and electricity flows is effective while it is performed simultaneously with the elaboration of thermal circuits of CHP by insertion heat accumulators and absorption lithium bromide heat pumps (ALBHP) in the structure of CHP; the mentioned insertion amends thermodynamic as well as economic and environmental indicators of CHP renovation and also develops CHP maneuverability. The ability of CHP to provide heat in required quantity, their capacity to change electricity generation output without excessive fuel consumption is extremely relevant for the energy system that incorporates thermal power plants as dominating component. At the same time the displacement of traditional electrical power regulators take place. Implementation of projects of this kind requires the elaboration of CHP flow diagram calculation methods and determining relevant indicators. The results of the numerical study of the energy characteristics of CHP with the aid of the topological models of the existing heat flow diagrams of CHP that incorporate ALBHP for recovery of low-temperature waste of heat flows of systems of cooling water circulating are presented in the article. An example of calculation, the results of the CHP thermodynamic efficiency evaluation, the change of the energy characteristics for different modes of operation of CHP caused by implementation of ALBHP are shown. The conditions for the effective application of lithium bromide absorption heat pumps are specified, as well as the rate of increase of thermodynamic efficiency; the changes of maneuverability of CHP with high initial parameters are identified, the natural gas savings in The Republic of Belarus are determined.