The techno-economic justification for the changing of a system for separate heating/cooling and electrical energy production with a CCHP system with a micro-turbine and absorption refrigeration unit

Abstract

Original scientific paper The system of separate production of heat energy from a boiler and cooling energy from a compression refrigeration unit powered with electrical energy from an external network can be replaced with a CCHP system based on the operation of a gas turbine and absorption refrigeration unit. For this purpose, models of the system were derived through the use of the object-oriented programming language Modelica, on the basis of which steady-state simulations were carried out, as well as technical-economic and the sensitivity analysis of the system, in relation to the changes of influential parameters such as coefficient of performance, the boiler efficiency, the ratio of the electric load, costs of electrical energy, fuel prices and investment costs. Developed system model is intended to be used in further research for dynamic simulations with implemented dynamic boundary conditions. Keywords: absorption refrigeration unit; CCHP; compression refrigeration unit; micro-turbine; Modelica; sensitivity analysis; SimulationXTehno-ekonomska opravdanost zamjene sustava odvojene proizvodnje toplinske/rashladne i električne energije CCHP sustavom s mikroturbinom i apsorpcijskim rashladnim uređajem Izvorni znanstveni članak Sustav odvojene proizvodnje toplinske energije iz kotla, energije za hlađenje iz kompresijskoga rashladnog uređaja i električne energije iz vanjske mreže može se zamijeniti CCHP sustavom koji se temelji na radu plinske turbine i apsorpcijskoga rashladnog uređaja. Za tu su namjenu napravljeni su modeli sustava primjenom objektno orijentiranog programskoga jezika Modelica, na temelju kojih su vršene simulacije za stacionarna stanja i izvedena tehnoekonomska analiza te analiza osjetljivosti sustava u ovisnosti o promjeni parametara kao što je faktor hlađenja, stupanj iskoristivosti kotla, omjer električnog opterećenja, cijena električne energije, cijena goriva i trošak investicije. Razvijeni model sustava koristiti će se u istraživanjima koja slijede za dinamičke simulacije s uvedenim dinamičkim rubnim uvjetima.

A gas turbine combustion chamber modeling by physical model

“…The special interest is in the area of the separate produc-separate production of heat energy from a boiler and cooling energy from a compression refrigeration unit. These are powered with electrical energy from an external network which could be replaced with a CCHP system (combined cooling, heating and power -combined cooling, heating and electricity generation) based on the operation of a gas turbine and absorption refrigeration unit [23,24]. The mentioned models are given to be described by differential-algebraic equations (DAE).…”