Thermodynamic investigation of a shared cogeneration system with electrical cars for northern Europe climate

Transition to alternative energy systems is indicated by EU Commission as a suitable path to energy efficiency and energy saving in the next years. The aims are to decrease greenhouses gases emissions, relevance of fossil fuels in energy production and energy dependence on extra-EU countries. These goals can be achieved increasing renewable energy sources and/or efficiency on energy production processes. In this paper an innovative micro-cogeneration system for household application is presented: it covers heating, domestic hot water and electricity demands for a residential user. Solid oxide fuel cells, heat pump and Stirling engine are utilised as a system to achieve high energy conversion efficiency. A transition from traditional petrol cars to electric mobility is also considered and simulated here. Different types of fuel are considered to demonstrate the high versatility of the simulated cogeneration system by changing the pre-reformer of the fuel cell. Thermodynamic analysis is performed to prove high efficiency with the different fuels

Thermodynamic and Thermoeconomic investigation of an Integrated Gasification SOFC and Stirling Engine

Thermodynamic and thermoeconomic investigation of a small scale Integrated Gasification Solid Oxide Fuel Cell (SOFC) and Stirling engine for combined heat and power (CHP) with a net electric capacity of 120kW have been performed. Woodchips are used as gasification feedstock to produce syngas which is then utilized for feeding the anode side of SOFC stacks. Thermal efficiency of 0.424 LHV for the plant is found to use 89.4kg/h of feedstock for producing 120kW of electricity. Thermoeconomic analysis shows that the production price of electricity is 0.1204$/kWh. Further, hot water is considered as a by-product and the cost of hot water was found to be 0.0214$/kWh. When compared to other renewable systems at similar scale, it shows that if both SOFC and Stirling engine technology emerges enter commercialization phase, then they can deliver electricity at a cost rate which is competitive with corresponding renewable systems at the same size and therefore.<br/

Performance Comparison on Repowering of a Steam Power Plant with Gas Turbines and Solid Oxide Fuel Cells

Repowering is a process for transforming an old power plant for greater capacity and/or higher efficiency. As a consequence, the repowered plant is characterized by higher power output and less specific CO2 emissions. Usually, repowering is performed by adding one or more gas turbines into an existing steam cycle which was built decades ago. Thus, traditional repowering results in combined cycles (CC). High temperature fuel cells (such as solid oxide fuel cell (SOFC)) could also be used as a topping cycle, achieving even higher global plant efficiency and even lower specific CO2 emissions. Decreasing the operating temperature in a SOFC allows the use of less complex materials and construction methods, consequently reducing plant and the electricity costs. A lower working temperature makes it also suitable for topping an existing steam cycle, instead of gas turbines. This is also the target of this study, repowering of an existing power plant with SOFC as well as gas turbines. Different repowering strategies are studied here, repowering with one gas turbine with and without supplementary firing, repowering with two gas turbines with and without supplementary firing and finally repowering using SOFC. Plant performances and CO2 emissions are compared for the suggested repowered plants