Integration of combined heat and power energy systems with gas turbine in locally integrated energy sectors

Abstract

World energy consumption has been increasing drastically due to the increment world population, with the high consumption from industry, residential, commercial and community service buildings. Locally Integrated Energy Sector (LIES) is introduced to minimize the energy consumption for the commercial and residential units integrated. The LIES concept extended from the Pinch Analysis-based multiple-processes Heat Integration considers energy intermittency and storage. The LIES started from thermal energy conservation, then extended to power and heat energy optimisation. The methodology aimed to maximize the energy recovery between processes across time for minimizing the overall energy consumption, which lead to energy and operating cost saving. The system integrates with steam turbines and energy storages (heat and power) to minimize the waste heat available in the LIES system. This research focuses on the energy source for overall LIES system, which the conventional boiler is replaced with a combined cycle CHP system with gas turbine. The CHP system consumes natural gas to generate heat and power energy for the system. The sequence of heat and power optimisation, via heat and power integration, is also studied in this research. The design and operating parameter of the gas turbine system is affected by the sequences of optimisation. The CHP system operates to fulfil the heat demand or power demand at the first place, which leads to different overall consumptions. The integration options are compared based on the overall energy consumption and operating costs. Result shows that the power-to-heat optimisation has the least overall energy consumption (1,434 kW/y), which contributes to the highest annual energy saving and operation cost saving (203,397 USD/y).