2. MethodThe schematics of the orig

2. MethodThe schematics of the original heat exchanger andthe modified design are shown in Figure 1. Like anyresidential hot water boiler, heat is generated by a burnerinside of the heat exchanger. The heat will later beabsorbed by the water passing through the heatexchanger. The rich-burn of methane generates acombination of hydrogen and carbon monoxide calledsyngas which is an effective fuel for FFCs [6]. Thenatural gas flow rate is fixed, while the amount ofcombustion air is controlled to get a desired rich-burnequivalence ratio. Once the syngas was generated, it wassent to the anode and acted as the fuel for the fuel cellchemical reaction. At the same time, air was fed to thecathode. The concept of fuel cell stack integration withthe boiler is shown in Figure 1b.The equivalence ratio was controlled by the throttlescrew of the blower which is normally used to regulatethe air supply to the burner’s combustion process. Bytightening it up, less air was allowed to get into thecombustion chamber so that high equivalence ratiocould be obtained. The combustion exhaust was sent to agas analyzer for the determination of the exhaustcomposition and air to fuel ratio. Natural gas flow ratewas measured by a natural gas meter. Based on this data,the equivalence ratio could be calculated.A planar Yttria Stabilized Zirconia (YSZ) cell wasselected for the model exhaust test as the combustionchamber temperature was measured to be in the range of850-1000°C. The anode was fabricated by dry pressing a60-40 ratio by weight of Nickel Oxide (NiO) and YSZ,and then sintered at 1000°C for 2 hours. When the anodewas cooled down, the YSZ electrolyte layer was sprayedonto it and then sintered at 1400°C for 4 hours. Finally,the cathode was sprayed with a 60-40 ratio by weight ofLanthanum Strontium Manganite (LSM) and YSZ, thensintered at 1100°C for 2 hours