Fuel Cell Cogeneration System Research Articles

Environmental and Efficiency Analysis of Simulated Application of the Solid Oxide Fuel Cell Co-Generation System in a Dormitory Building

The problem of air pollution in Korea has become progressively more serious in recent years. Since electricity is advertised as clean energy, some newly developed buildings in Korea are using only electricity for all energy needs. In this research, the annual amount of air pollution attributable to energy under the traditional method in a dormitory building, which is supplying both natural gas and electricity to the building, was compared with the annual amount of air pollution attributable to supplying only electricity. The results showed that the building using only electricity emits much more air pollution than the building using electricity and natural gas together. Under the traditional method of energy supply, a residential solid oxide fuel cell cogeneration system (SOFC–CGS) for minimizing environmental pollution of the building was simulated. Furthermore, as a high load factor could lead to high efficiency of the SOFC–CGS, sharing of the SOFC–CGS by multi-households could increase its efficiency. Finally, the environmental pollution from using one system in one household was compared with that from sharing one system by multi-households. The results showed that the environmental pollution from sharing the system was relatively higher but still similar to that when using one system in one household.

Energy performance and CO2 emissions of fuel cells for residential application in Chinese hot summer and cold winter areas

The energy consumed in residential buildings has become a key factor in China. An energy-efficient and low-emission fuel cell co-generation system (FC-CGS) is a promising electric and thermal energy generation technology to enhance the energy-saving effects for residential application. SOFC-CGSs and PEFC-CGSs are the two major types of residential FC-CGSs. This paper aims to analyze the energy-saving effects of FC-CGSs for residential buildings in Chinese hot summer and cold winter areas. Changsha city is selected as an example. This study at first outlines SOFC-CGSs and PEFC-CGSs, introduces the simulation methods and develops a standard family model for simulation, then calculates domestic demands of the system, and finally compares the primary energy consumption and CO2 emissions of FC-CGSs with those of a traditional power and heat generation system based on gas and electricity. The results show that residential PEFC-CGSs offered primary energy reduction of 8.8% in winter. However, the average reductions of primary energy and CO2 emissions of SOFC-CGSs were 15.1% and 9.9%, respectively.

Analysis of electricity usage habits based on electricity and hot water supply demand detail measurement of 10 houses

In recent years, energy-generating devices such as residential use fuel cell cogeneration systems (FCCGS) have been spreading. A solid polymer electrolyte fuel cell (PEFC), which is a type of FCCGS, determines the amount of power generation and power generation time according to the demand for electricity and hot water supply in houses. Therefore, residents’ lifestyle influences a PEFC’s load following speed and efficiency. However, there are few actual surveys of household electricity and hot water supply demand, and we haven’t fully grasped factors that affect them. Therefore, we aim to acquire home electricity and hot water usage habits that affect PEFC operation by measuring detailed electricity and hot water supply demand in 10 houses in Japan. In addition, we also conducted a questionnaire survey for the households and analysed the influence of resident’s behaviour on demand for electricity and hot water supply. We can’t see instantaneous changes in the amount of PEFC generated based on hourly data, so we measured the electricity consumption of the entire house and the electricity consumption and hot water consumption of each household appliance every 2 seconds. In this report, we analysed the usage habits of home appliances.

Performance Analysis of a Direct Carbon Fuel Cell Cogeneration System Combined with a Two-Stage Thermoelectric Generator

Performance Analysis of a Direct Carbon Fuel Cell Cogeneration System Combined with a Two-Stage Thermoelectric Generator

Analysis of operation plans of residential PEFC–CGS: a perspective of cost optimality under demand uncertainty

This study mainly aimed to compare operation planning schemes for polymer electrolyte fuel cell cogeneration systems (PEFC–CGSs) to analyze derived operation plans from various perspectives. PEFC–C...

Numerical modeling of an automotive derivative polymer electrolyte membrane fuel cell cogeneration system with selective membranes

Cogeneration power plants based on fuel cells are a promising technology to produce electric and thermal energy with reduced costs and environmental impact. The most mature fuel cell technology for this kind of applications are polymer electrolyte membrane fuel cells, which require high-purity hydrogen.The most common and least expensive way to produce hydrogen within today's energy infrastructure is steam reforming of natural gas. Such a process produces a syngas rich in hydrogen that has to be purified to be properly used in low temperature fuel cells. However, the hydrogen production and purification processes strongly affect the performance, the cost, and the complexity of the energy system.Purification is usually performed through pressure swing adsorption, which is a semi-batch process that increases the plant complexity and incorporates a substantial efficiency penalty. A promising alternative option for hydrogen purification is the use of selective metal membranes that can be integrated in the reactors of the fuel processing plant. Such a membrane separation may improve the thermo-chemical performance of the energy system, while reducing the power plant complexity, and potentially its cost. Herein, we perform a technical analysis, through thermo-chemical models, to evaluate the integration of Pd-based H2-selective membranes in different sections of the fuel processing plant: (i) steam reforming reactor, (ii) water gas shift reactor, (iii) at the outlet of the fuel processor as a separator device. The results show that a drastic fuel processing plant simplification is achievable by integrating the Pd-membranes in the water gas shift and reforming reactors. Moreover, the natural gas reforming membrane reactor yields significant efficiency improvements.

Temperature Dependence on Oxygen Reduction Reaction for Carbon-Supported Pd-Core/Pt-Shell Electrocatalysts

Introduction Polymer electrolyte Fuel Cells (PEFCs) have been developed for the electric device applications such as residential fuel cell cogeneration system and fuel cell vehicles. PEFC cathode catalyst requires an excess amount of platinum due to the degradation of oxygen reduction reaction (ORR) activity at acidic environment and slow reaction kinetics at low temperature. Therefore, it is important to reduce the use of platinum in the catalyst and improve its catalytic activity as well as durability. Core-shell structure is one of the solutions to achieve a higher catalytic activity, higher durability and less use of platinum. However, the factor of controlling ORR activity in core-shell catalyst still has not well understood such as potential/temperature-dependent surface structures and oxidation states of platinum. Convection voltammetry using rotating disc electrode (RDE) is one of the usable ways for evaluating ORR activity of cathode catalyst materials for PEFCs. However, the correlation between ORR activity and the electronic as well as local structure of these materials casted on RDE is not fully clear yet. In this paper, we report the temperature dependency of ORR activity of TEC10V30E Pt/C catalysts (T.K.K.) and Pd-core/Pt-shell/C catalysts from 25 oC to 60 oC, combining RDE measurements and Operando X-ray absorption spectroscopic measurements (XAS). We investigated the correlation with the electronic structure / local structural parameters of the Pt/C catalyst and investigated the factors that govern the oxygen reduction reaction activity on the RDE surface from the viewpoint of temperature dependency. In this research, we synthesized the 1 mono-layer platinum shell on the carbon-supported palladium (Pt-Pd/C) by copper under potential deposition method and investigated its ORR activity at different temperatures and the state of platinum by rotating disk electrode (RDE) measurements and operando X-ray absorption fine structure (XAFS) respectively. The effect of oxygen coverage at Pt surface on ORR activity was mainly discussed. Experimental A model electrode was prepared by applying a catalyst ink prepared from TEC 10 V 30 E Pt / C (TKK) to the surface of glassy carbon RDE. The 1 mono-layer platinum shell on the carbon-supported palladium (Pt-Pd/C) by copper under potential deposition method. The electrochemical cell was constructed using a model electrode fabricated in the working electrode, a Pt mesh for the counter electrode, a reversible hydrogen electrode for the reference electrode, and 0.1 M HClO4 aq for the electrolyte. Electrochemical surface area was calculated by CV measurement under N2 saturated condition and area specific activity value was determined by LSV measurement under N2 and O2 saturated conditions. Measurements were carried out at 10, 25, 40, 50, 60 ºC. For this model electrode, operand XAS measurement of Pt LIII -edge and Pt LII -edge were carried out by using the beamline BL37XU/BL01B1 in SPring-8 (Japan). The measurements were performed by a fluorescent method using a temperature variable type Operand cell that can directly measure the electrocatalyst applied to RDE (Fig. 1). The number of Pt 5d orbital vacancies was calculated from the obtained XANES spectrum, and the local structure of Pt was analyzed from the EXAFS spectrum. The oxygen reduction activity performance in the electrochemical measurement was evaluated from the area specific activity value at 0.9 V of the Pt / C catalyst at 10, 25, 40, 50, 60 ºC. The oxygen reduction activity of the model electrode is determined by the electrochemical parameters related to the oxygen reduction reaction such as the oxygen coverage. Results and discussion According to RDE results, Pt-Pd/C has a potentially higher ORR specific activity than the conventional Pt/C at low temperature (< 50℃) while its catalytic activity has suddenly deteriorated over 60℃. Linear sweep voltammetry showed the coverage of oxygen species at Pt surface dramatically increased at high temperature in 1.1 V (vs. RHE). This oxygen species could reduce the ORR by blocking active sites for additional O2 adsorption. We also found the rapid increase of Pt 5d orbital vacancy by X-ray absorption spectra with the temperature, indicating that Pt on Pd/C was more easily oxidized over 60℃ than Pt/C.

LCA分析とDEAを用いた家庭用燃料電池システムにおける環境性及び性能を考慮した指標（FC-DEA）の提案

LCA分析とDEAを用いた家庭用燃料電池システムにおける環境性及び性能を考慮した指標（FC-DEA）の提案

A region-specific analysis of technology implementation of hydrogen energy in Japan

A new energy system using adequate energy carriers such as hydrogen is needed for filling out the spatial and temporal gaps in energy supply and demand to promote renewable-derived energy systems. The environmental implementation effects of technologies associated with energy carriers should be carefully examined because the conditions of the supply chain depend on region-specific characteristics. In this study, an approach of analyzing the implementation effects considering regional characteristics with energy balance simulation model is proposed. As a case study, the potential mitigation of life-cycle greenhouse gas emission by substituting fuel cell vehicles and stationary fuel cell cogeneration systems in households for conventional vehicles and energy supply systems was visualized for two kinds of regions with different classification policies; i.e., prefectures and urban employment areas in Japan. The case study indicated that regional characteristics such as the annual travel distance per car, number of cars, and the power and heat demand strongly affect the implementation effects. Our proposed approach can effectively match technologies with regions, which can be useful for decision-makers.

燃料電池による一次エネルギー削減効果に関する研究 その2 一般電気事業者を対象とした一次エネルギー及びCO2の時刻別原単位に関する解析と関西エリアにおける一次エネルギー及びCO2削減量

燃料電池による一次エネルギー削減効果に関する研究 その2 一般電気事業者を対象とした一次エネルギー及びCO2の時刻別原単位に関する解析と関西エリアにおける一次エネルギー及びCO2削減量

Technological assessment of residential fuel cells using hydrogen supply systems for fuel cell vehicles

Widespread of the fuel cell vehicles (FCV) is one of the essential solutions to CO2 emission mitigation. However there were only 81 working hydrogen stations distributed in Japan in January 2017. Therefore, it has become increasingly necessary to establish the hydrogen stations. In this study, we focus on the unutilized hydrogen production capacity of a fuel processor system (FPS) incorporated in a residential fuel cell cogeneration system. We proposed a system which the FPS and fuel cell stacks are operated independently at their respective efficient load factors, and which can produce hydrogen for the FCV using the unutilized capabilities of the FPS. An optimum scheduling model for the operation of the FPS and the fuel cell stacks was developed to evaluate annual hydrogen production for the FCV for 24 households. As the results, it was found that all households have the capacity to produce at least 1,040 Nm3/year of hydrogen, which a FCV can run 8,000 km in a year. Furthermore, we evaluated the primary energy reduction potential were in relation to the different power and hot water demands. As the results, it was found that the primary energy reduction effect slightly increases with increasing hydrogen supply up to about 8,000 km worth of FCV hydrogen.

4-11 定置用燃料電池システムの低コスト化・高性能化技術の実用性評価((3)燃料電池(1),Session 4 新エネルギー,研究発表(口頭発表))

4-11 定置用燃料電池システムの低コスト化・高性能化技術の実用性評価((3)燃料電池(1),Session 4 新エネルギー,研究発表(口頭発表))

Development of New Model of Fuel Cell Systems

Tokyo Gas has developed a residential fuel cell CHP system named “ENE-FARM” jointly with Panasonic, and began to sell ENE-FARM as the world’s first commercial fuel cell cogeneration system in May 2009. Following the first-generation model of ENE-FARM, the second-generation was released in 2011, and the third-generation in 2013. The cumulative sales of ENE-FARM have reached 40,000 units as of January 2015. After the third-generation, the new fourth-generation model of ENE-FARM has been launched since April 2015. This new model was developed in order to meet customer expectations such as reduced cost, integration of optional units for a power outage and greater flexibility of installation. These improvements can contribute to the customer satisfactions and the expansion of ENE-FARM spread. In this paper, specifications and main features of the new model ENE-FARM are described

Review on the Recent Developments of Photovoltaic Thermal (PV/T) and Proton Exchange Membrane Fuel Cell (PEMFC) Based Hybrid System

Photovoltaic Thermal (PV/T) system emerged as one of the convenient type of renewable energy system acquire the ability to generate power and thermal energy in the absence of moving parts. However, the power output of PV/T is intermittent due to dependency on solar irradiation condition. Furthermore, its efficiency decreases because of cells instability at high temperature. On the other hand, fuel cell co-generation system (CGS) is another technology that can generate power and heat simultaneously. Integration of PV/T and fuel cell CGS could enhance the reliability and sustainability of both systems as well as increasing the overall system performance. Hence, this paper intended to present the parameters that affect performance of PV/T and Proton Exchange Membrane Fuel Cell (PEMFC) CGS. Moreover, recent developments on PV/T-fuel cell hybrid system are also presented. Based on literates, mass flow rate of moving fluid in PV/T was found to affect the system efficiency. For the PEMFC, when the heat is utilized, the system performance can be increased where the heat efficiency is similar to electrical efficiency which is about 50%. Recent developments of hybrid PV/T and fuel cell show that most of the studies only focus on the power generation of the system. There are less study on the both power and heat utilization which is indeed necessary in future development in term of operation strategy, optimization of size, and operation algorithm.

集合住宅を対象とした燃料電池コージェネレーションシステム普及シナリオの作成

Fuel cell cogeneration is one of promising energy-saving technologies in pursuit of a sustainable society. However, it is unpredictable how many fuel cell cogeneration systems will be diffused since there are many future uncertainties, such as people's lifestyles and national energy policies. As an approach to tackling with this problem, this paper proposes a method for describing scenarios to analyze the diffusion of residential energy systems, such as fuel cell cogeneration systems. We develop a simulation model for estimating the diffusion of residential energy systems, in which conjoint analysis is undertaken to analyze consumers' preferences. In a case study, several scenarios are described for analyzing the diffusion of solid oxide fuel cell (SOFC) cogeneration systems for apartment houses, where the region of interest is Kansai Area, Japan from 2013-2030. The described scenarios differ in terms of nuclear energy policies. The results show that the number of fuel cell cogeneration systems in 2030 reaches 147-157 thousands depending on the share of nuclear power. In addition, it is revealed that monthly utility cost has a much larger impact on SOFC diffusion than CO2 emissions. Future work includes further what-if analyses of the scenarios to identify factors that would give a significant influence on SOFC diffusion.

S0830203 家庭用PEFC-CGSにおける需要予測精度が省エネルギー性に与える影響の分析

The main objective of this study is to clarify the impact of energy demand prediction accuracy on optimal operating result of residential energy supply system. In this paper, the energy system consists of polymer electrolyte fuel cell cogeneration system and electrical-driven heating, ventilating and air conditioning system. Primary energy of operational results with various demand prediction patterns are calculated in order to analyze the effect of demand prediction error. As a result, it is concluded that prediction error of energy demand causes 54.3 MJ/day increase of daily primary energy in the worst case, and annual primary energy consumption can be reduced by 13.2% with the best prediction in comparison with the worst one. Furthermore, the impact of energy demand prediction accuracy on daily primary energy has relationship with the amount of hot water demand. Therefore, the effectiveness of using the amount of hot water demand as a parameter for demand prediction is suggested in terms of energy saving.

電力・給湯需要のばらつきが固体酸化物形燃料電池コージェネレーションシステムの導入効果に与える影響&lt;br&gt;集合住宅へのコージェネレーションシステムの導入方法に関する研究 その1

Installation of residential solid-oxide fuel cell cogeneration system (SOFC-CGS) has been promoted as an energy-saving measure. Although SOFC-CGS is becoming popular among detached housing, the installation of SOFC-CGS in apartment buildings can also be effective in reducing residential energy consumption. In this study, the effectiveness of SOFC-CGS installation in an apartment building is evaluated by considering the variation of eletricity and hot water demands in different household settings. In order to simulate the demands, parameters are formulated and randomly distributed in a 50-unit apartment building model. The reduction rate of energy consumption by SOFC-CGS installation is generated for each unit and the impact of each parameter is examined.

S0830104 実測に基づく燃料電池・コージェネレーションシステムの特性評価に関する研究

S0830104 実測に基づく燃料電池・コージェネレーションシステムの特性評価に関する研究

Improved Optimal Operation Planning Method Based on Tabu Search for Residential PEFC-CGS Considering Ramping Rate

This paper proposes an improved optimal operation planning method for residential PEFC-CGS (Polymer Electrolyte Fuel CellCo-Generation System). Residential PEFC-CGS has recently been gathering attention as one of the distributed power sources with high efficiency and low environmental impacts. Previous research pointed out that the output variations of PEFC adversely affect the durability. It can be surmised that smaller output variations will be desired to extend durability years. However, in this field, ramping rate have not been sufficiently considered. For local search and tabu search, ramping rate constraint makes our operation planning difficult because it restricts the search for feasible neighborhood solutions. Therefore, the authors proposed a method to deal with typical and harsher ramping rate constraints in comparison with conventional methods. There are two key points for the improvement. One is the reinforcement of the search along the output power axis; the other is to make use of the strategy of tabu search which avoids the local optimal solutions. The simulation results show the effectiveness of the proposed method in the daily operation planning. Furthermore, in the case using typical ramping rate parameter, it is confirmed that tabu search doesn’t contribute the reduction of daily operational cost due to the above stated restriction of the search area.

Energy saving evaluation of PEFC systems with solar cell and battery

The main objective of this study is to evaluate energy saving potentials of polymer electrolyte fuel cell cogeneration systems integrated with solar cell and battery installed into residential houses. There exist many alternative operational policies in the above systems, and the mathematical planning approach is taken to derive the rational system's operational solution based on the mixed-integer linear planning method. In the numerical analysis of this study, energy saving characteristics of 12 alternative systems are compared respectively, and as one of main obtained results, it become clear that the energy saving effects to install battery into the systems depend largely on the operational policy of the system together with the evaluation criterion of adverse electricity from the solar cell to the electric grid. In other words, in the case of giving high priority to the self-consumption of electricity from the solar cell within the house, the energy saving potential to install battery increases largely, but few effects are noticed in other cases.