Techno-economic assessment of high efficient energy production (SOFC-GT) for residential application from natural gas
Introduction
Nowadays, finding efficient power systems is one of the major concerns, especially with the depletion of fossil fuel sources over time. Energy demands are expected to keep increasing in the future. The energy roadmaps indicate that the world energy consumption is expected to increase approximately 40 percent during 2006–2030 (Energy Information Administration, 2009). The efficiency of conventional thermal plants is usually less than 39% where most of the energy is lost as the waste heat. Therefore, the consideration of an efficient system that can effectively utilize the waste heat is crucial for the improvement of overall plant efficiency. Thus, finding an efficacious system is vital to increase the unit of the produced energy per unit of the consumed fuel (Al-Sulaimana et al., 2010).
Fuel cells have attracted considerable interest during recent years. Among the different types, solid oxide fuel cell (SOFC) technology is very promising because of its high efficiency, less polluting, fuel flexibility and high temperature of the exhaust heat, which can be used for additional electricity generation through cogeneration (Singhal and Kendal, 2003). The most typical hybrid configuration suggested in the literatures is an integrated gas turbine process with the SOFC as the core of the system. The prediction of electrical efficiency for such a system is more than 60 percent (Costamagna et al., 2001). Recently, many researchers have studied SOFC-GT hybrid system from thermodynamic and economic points of view. Table 1 shows a number of these studies and important results of them.
The main goals of this study are as follow.
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Introduction of an efficient hybrid cycle (SOFC-GT) as an electrical and heating energy supplier for a residential area and in each specific climate area.
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Sensitivity analyses of fuel cost and market price of the suggested system product is performed to find a solution for the substitution of a traditional power production with an introduced system.
Application of SOFC-GT to supply the electrical and heating demands of a residential area is examined in this article. A four floor building is considered for this purpose and the electrical, heating and cooling load of considered building are calculated for four different climate areas. In the next step, the thermodynamic modeling of SOFC-GT combined heat and power system is considered. Then, by using energy demand of the building, the size of power generation system is calculated. After that, the rate of energy production and consumption in different months of a year at these four points are calculated and the rate of extra energy is determined as well. The economic analysis evaluates the proposed project from the economic point of view in the last part of this study.
Fig. 1 shows the scheme of examined system. The structure of suggested system is based on the industrial sample by Siemens Westinghouse (Siemens) but it is developed by the author to supply the electrical energy-cooling and heating demand of the building. This system consists of solid oxide fuel cell, internal reformer, fuel compressor, air compressor, gas turbine and three heat exchangers. The preheated air and fuel enters the fuel cell and after that, the extra fuel is ignited in the combustor. Then the hot flow gas enters the gas expander for second stage of power generation (first stage is happens in SOFC). To prevent the waste of energy from the gas turbine stack, two heat exchangers (air recuperator and fuel recuperator) are used for pre-heating air and fuel before entering SOFC.
All simulations are carried out by using the Matlab commercial code.
Section snippets
Calculation of cooling and heating energy
As mentioned before, a four floor building is considered in this study. Each floor has the 100 m2 flat.
Fig. 2 shows the scheme of the considered building. Table 2 indicates the characteristics of the considered building.
The heating load of the building is supplied by the generated hot water from SOFC-GT cycle. The heating system of building is central and the circulated water from the floors of building is used as the inlet of water heater. The heat losses in the pipelines are neglected but the
Results of building energy modeling
According to the energy model of the building which is developed before, Table 9 shows the energy consumption in cooling, heating and electrical instruments of each floor. In power consumption calculation, it is assumed that all the electrical instruments are activated in the same time and the power generation system should supply all of them. Also the cooling load in selected cities is prepared by SOFC-GT electrical power (Air condition unit) but for heating load, the required energy is
Conclusion
Simulation and economic assessment of SOFC-GT in household application is subjected in this article. Results of simulation indicate that the maximum power of SOFC-GT power system can be approached in the limiting current density. So, this value is chosen as an operational set point for SOFC-GT power cycle. The cooling, heating and electrical energy consumption of the 100 m2 building are computed and applied for sizing the SOFC-GT power cycle in selected cities. The maximum power consumption
References (22)
- et al.
Solid oxide fuel cell application in district cooling
J. Power Sources
(2014) Thermoeconomic modeling and parametric study of hybrid SOFC-gas turbine-steam turbine power plants ranging from 1.5 to 10 MW
J. Power Sources
(2008)Energy and exergy analysis of internal reforming solid oxide fuel cell-gas turbine hybrid system
Int. J. Hydrog. Energy
(2007)Thermodynamic model and parametric analysis of a tubular SOFC module
J. Power Sources
(2001)- et al.
A complete polarization model of a solid oxide fuel cell and its sensitivity to the change of cell component thickness
J. Power Sources
(2001) - et al.
Modeling of simple hybrid solid oxide fuel cell and gas turbine power plant
J. Power Sources
(2002) - et al.
Energy and exergy analysis of simple solid-oxide fuel-cell power systems
J. Power Sources
(2002) - et al.
Thermodynamic modeling of direct internal reforming solid oxide fuel cells operating with syngas
Int. J. Hydrog. Energy
(2007) - et al.
Design and part-load performance of a hybrid system based on a solid oxide fuel cell reactor and a micro gas turbine
J. Power Sources
(2001) - et al.
Exergy based performance analysis of a solid oxide fuel cell and steam injected gas turbine hybrid power system
Int. J. Hydrog. Energy
(2009)
Assessment of economic viability for PV/wind/diesel hybrid energy system in southern Peninsular Malaysia
Renew. Sustain Energy Rev.
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