Illustration of the different PEM fuel cell stack components and a general operating principle.

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... acid fuel cells (PAFC), molten-carbonate fuel cells, solid oxide fuel cells (SOFC) and high/low temperature proton exchange membrane (PEM) fuel cells [7]. PEM fuel cells are specifically interesting for residential buildings since they operate in a temperature range between 30°C to 100°C [8] which is appropriate for household conditions. In Fig. 1 a schematic representation of a typical composition of a PEM fuel cell stack can be seen. Typically, a PEM fuel cell is composed out of two electrodes, two gas diffusion layers and an electrolytic membrane conducting protons [9]. In the PEM fuel cells, pure molecular gaseous hydrogen (H2) is used as the fuel and it is supplied at the ...

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... [s] Due to the optimization cycle, the voltage over and current from the fuel cell are not constant in time. Therefore, the current and voltage are averaged in time for each resistive load where the optimization cycles themselves were excluded from the averaging window. The resulting averaged voltage and current are shown in Fig. 10 for a series of eight tested resistances. The test shown in Fig. 10 is repeated an additional two times to verify the repeatability of the findings (i.e the averaging affects). Fig. 11 shows the results of these three tests, which do not differ significantly. The red colour represents the results of 5 connected resistances, the green ...

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... over and current from the fuel cell are not constant in time. Therefore, the current and voltage are averaged in time for each resistive load where the optimization cycles themselves were excluded from the averaging window. The resulting averaged voltage and current are shown in Fig. 10 for a series of eight tested resistances. The test shown in Fig. 10 is repeated an additional two times to verify the repeatability of the findings (i.e the averaging affects). Fig. 11 shows the results of these three tests, which do not differ significantly. The red colour represents the results of 5 connected resistances, the green 7, while the blue coloured curve gives the result for 8 resistances ...

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... for each resistive load where the optimization cycles themselves were excluded from the averaging window. The resulting averaged voltage and current are shown in Fig. 10 for a series of eight tested resistances. The test shown in Fig. 10 is repeated an additional two times to verify the repeatability of the findings (i.e the averaging affects). Fig. 11 shows the results of these three tests, which do not differ significantly. The red colour represents the results of 5 connected resistances, the green 7, while the blue coloured curve gives the result for 8 resistances connected in parallel. The voltage as a function of the current shown in Fig. 10 deviates from what would be expected ...

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... of the findings (i.e the averaging affects). Fig. 11 shows the results of these three tests, which do not differ significantly. The red colour represents the results of 5 connected resistances, the green 7, while the blue coloured curve gives the result for 8 resistances connected in parallel. The voltage as a function of the current shown in Fig. 10 deviates from what would be expected from the theory of a fuel cell outlined in the introduction. A reason for the deviation with the theoretical curve is the fact that the theory only considers a single fuel cell while the tested commercial fuel cell contains an array of individual connected cells. Furthermore, power electronics are ...

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... of a hydrogen fuel cell. However, some phenomena of the voltage current density curve can be explained based on the theoretical losses described in the introduction. The gradual drop in supplied potential can be explained by ohmic losses while the drop at the end of the voltage curve can be explained by concentration polarization losses. Fig. 12 shows the efficiency of the fuel cell as a function of the load. There is no significant change in the fuel cell efficiency as a function of the load. The official manual of the fuel cell states a minimal efficiency of 36.2% for a new fuel cell. The stated efficiency is not significantly different from the measured one. However, for ...

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... efficiency of 36.2% for a new fuel cell. The stated efficiency is not significantly different from the measured one. However, for the performed tests and applied monitoring equipment, the examined fuel cell could not reach the declared efficiency of 36.2%. Still, the declared efficiency is noted within the error margin of the used equipment. In Fig. 13 the measured exhaust temperature as a function of the applied resistive load can be seen. The exhaust temperature does not strongly fluctuate with the load. Furthermore, the exhaust air temperature is found to be too low to perform any additional cost effective heat recovery from the unit besides directly using the exhaust air. Thus, ...

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... system using the FCM-802, example data from a case study of an industrial partner was used. The case concerns a modern residential household located in Belgium in which the electrical power is used to supply the complete heating system (space heating and domestic hot water) with a swimming pool, electrical appliances and an electrical vehicle. Fig. 14 gives an illustrated overview of the analysed system. To cover the electrical energy demand, locally produced renewable energy out of the photovoltaic panels and wind turbine would be used. The shortage of energy production should be compensated from the FCM-802 fuel cell. Based on the input data, the total electricity demand of the ...

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... during the summer period when there is a surplus in renewable energy generation. The chosen electrolyser S40 is a product of the company Nel with the efficiency of 55% and energy use of 6.1 kWh per Nm 3 of produced hydrogen [19]. Besides the electrolyser, a compressor for storing the hydrogen at higher pressures is needed in the system as well. Fig. 15 gives an overview of the efficiencies of the used equipment and hence the overall system efficiency. With the surplus 6069 kWh of electricity, the installed electrolyser can produce 1994.9 Nm 3 of hydrogen leaving a shortage of 1138.02 Nm 3 . The total system efficiency of the hydrogen storage system is determined based on an assumed ...