MODELING AND EXPERIMENTAL VALIDATION OF THE AIR DELIVERY SYSTEM FOR SOLID OXIDE FUEL CELL POWER GENERATION

Distributed power generation systems can be used in the electric grid to reduce peak loads, raise power quality, and reduce/eliminate transmission losses. One distributed energy system with distinct advantages is the Solid Oxide Fuel Cell (SOFC) integrated with an Internal Combustion Engine (ICE). This research aimed to produce and test a high-efficiency air delivery system that supports the SOFC-ICE to generate power on the scale of 80 kW, which has the capability to operate at electric efficiencies as high as 70%. The air balance of plant (BOP) is designed to create cost-effective preheating. To accomplish this, the system utilizes low-speed scroll-type rotating compressors alongside brazed plate and frame heat exchangers. The scroll compressors were modeled in Gamma Technologies Suite (GT-Suite) and the remaining air BOP system was modeled with thermodynamic and heat transfer equations. Testing was done on the compressors and heat exchangers to validate the model, which was used to predict performance over a range of conditions. Both compressors were operated between 20 g/s and 60 g/s, while the temperature was swept from 200°C to 600°C, which yielded compressor efficiencies over 60% and heat exchanger effectiveness over 0.90. The validated model was used to predict performance at full power and in part-load conditions. A turn-down analysis was conducted with a ratio of 3:1 to see how the system would perform at start-up, part-load, and full-load conditions.