Energy, Exergy and Economic Analyses of a Combined Heating and Power System with Turbine-Driving Fans and Pumps in Northeast China

Abstract

The combined heating and power (CHP) system with turbine-driving fans and pumps is more efficient and economical in meeting heat demand in cold areas, however, there are no detailed studies that investigate its thermodynamic performance, improvement possibilities and economy. In this paper, the energy, exergy and economic analysis of a CHP system with turbine-driving fans and pumps operated in Northeast China were conducted to provide insights into improvement options. It is revealed that the boiler is the main source of exergy destruction, followed by the steam-water heat exchangers (SWHE), temperature and pressure reducer (TPR), turbines, and deaerator. The energy and exergy efficiencies of the system are 89.72% and 10.07%, while the boiler’s are 84.89% and 30.04%. The thermodynamic performance of the boiler and turbines are compared with other studies, and the inefficiencies of major components are analyzed and some advice for further improvement is given. As the reference state changes, the main conclusions stay the same. The turbine-driving mode saves an electricity cost of 16,654.08 yuan on 15 December 2018. The effect of electricity price and on-grid price on the saved daily electricity cost is investigated and it proves that the turbine-driving mode is more economical in China.

Investigation of the thermodynamic performance of an existing steam power plant via energy and exergy analyses to restrain the environmental repercussions: A simulation study

“…The analysis shows that with the increase in temperature and pressure of the superheated steam (from the boiler), the steam flowrate requirement is decreased. This case-study is also in agreement with the research conducted by various researchers [27,29,30].…”

“…The comparatively reduced amount of carbon is un-combusted, decrease in ash/residue production rate which helps in improved % exergy efficiency of the boiler. This case-study is also in agreement with the research conducted by various researchers [20,[27][28][29][30]. The analysis shows that with the increase in temperature and pressure of the superheated steam (from the boiler), the steam flowrate requirement is decreased.…”

“…Increase in temperature of the system results in the increase in the superheating degree, which leads to the improved operational efficiency of the steam turbine. This case-study is also in agreement with the research conducted by various researchers[27,29,30]. represents the effect of superheated steam temperature and pressure on the steam requirements by the steam turbine, keeping electricity production capacity same i.e., 2.97 MW.…”

Combined heat and power plant using a multi-objective Henry gas solubility optimization algorithm: A thermodynamic investigation of energy, exergy, and economic (3E) analysis

“… Boyaghchi and Molaie, 2015 Combined cycle ✗ ✓ ✗ ✗ 420 The sensitivity of the various components of exergy loss was studied in a practical combined cycle power plant. Li et al, 2020 Combined cycle ✓ ✓ ✓ ✗ 1989 In cold climes, a CHPP system with turbine-driven fans and pumps is more efficient and effective in providing heat demand. …”

The Exploitation of Low-Temperature Hot Water Boiler Sources with High-Temperature Heat Pump Integration

“…Calise et al [10] have provided an overview of recent progress in assessing sustainable energy systems. Li et al [11] have analysed the economic and energy efficiency of CHP (cogeneration heat and power) systems with turbine-driven fans and pumps. Liu et al [7] have developed a mathematics and results have shown that a CO 2 heat pump system is economically and ecologically feasible, especially in areas not rich in natural gas.…”