MODELLING, SIMULATION AND OPTIMIZATION OF SMALL-SCALE CCHP ENERGY SYSTEMS

The article defines and discusses techno-economic models of CCHP system based on a power system with an internal combustion engine or a gas turbine with electric power of 0,2-1 MW including an absorption or vapour-compression refrigeration unit. The thermodynamic, ecological and economical features of the CCHP system under different load situations are analysed in relation to the basic model of energy generation with boiler and vapour-compression refrigeration unit. Based on the data of the equipment manufacturer, functional dependency curves of individual components are created in dependency to the load, which enables the construction of a system model composed of a power system (internal combustion engine or a gas turbine), single-stage or two-stage absorption refrigeration unit and boiler. A program solution has been developed applying the object-oriented programming language Modelica that enables the insight into the behaviour and techno-economic validity of usage of the analysed systems in transformable operating conditions. The article examines various energetic models, defining for the influential parameters (electric energy and fuel prices, investment costs and the level of heat recovery) the value of total energy efficiency, the return period on investment costs and the environmental impact concerns.