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Modeling studies have been carried out to investigate coupling of an solid oxide fuel cell auxiliary power unit (SOFC APU) with a small scale NH3–H2O based vapour absorption refrigeration system (VARS) for a refrigerated truck/trailer application, by using hot cathode exhaust from the SOFC stack to drive the VARS. A bottom up design and modeling approach has been adopted where the end requirements, cooling load in this case, are identified first followed by upstream modeling of the SOFC and VARS unit. This approach enables design of system/components to meet the desired end requirements rather than compromise or fall short of the desired goal.Initial modeling results show that it is indeed possible to couple an SOFC with a VARS on a small scale (< 10 kW cooling load) for the refrigerated truck application. As this novel strategy utilizes both heat and power from the SOFC it promises a higher total efficiency up to 80% and also removes a significant part of the load from the main diesel engine, thereby leaving the engine to carry out the task of only propelling the vehicle. The excess electrical power from the SOFC could also be used to charge the vehicle batteries.

A vapour absorption refrigeration system (VARS) coupled with a solid oxide fuel cell (SOFC) is proposed for different types of refrigerated trucks (large, medium and small) as a favourable alternative to conventional diesel engine driven vapour compression refrigeration systems. An SOFC-supported VARS has the novel attributes of negligible environmental impact and the ability to keep the refrigeration system running while the vehicle engine is switched off, In addition, the SOFC system produces electricity which can be utilised for other operations on the vehicle. This in turn reduces the load on the main diesel engine of the vehicle. This research paper presents a comprehensive thermo-economic study for two different SOFC system configurations namely; series and parallel to optimise the SOFC subsystem layout. Moreover, a benefit function to optimise the SOFC stack size and operating conditions has been identified considering four performance parameters, namely; thermodynamic efficiency, weight of the system, greenhouse gas (GHG) emissions, and cost of cogeneration. The analysis was conducted on various categories of refrigerated trucks. The results show that a parallel configuration has an enhanced thermo-economic performance and requires a 45-65% lower number of SOFC cells to obtain the required refrigeration load in comparison to the series configuration. Simulation results indicated that the proposed SOFC-VARS for large, medium and small refrigerated trucks can output 3.3 kW, 12.8 kW and 18.7 kW of electric power and 1 kW, 4 kW and 6 kW of refrigeration power respectively. It was also found that the SOFC-coupled VARS is able to cater to the required refrigeration load with negligible emissions of GHGs and zero emissions of particulate matter and NOx compared to other refrigerated transportation technologies.

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