Thermoeconomic assessment of an absorption refrigeration and hydrogen-fueled diesel power generator cogeneration system

• Higher system exergetic efficiency is achieved with increased use of hydrogen.
• Absorption refrigeration system exergetic efficiency decreases at high engine loads.
• Refrigeration system evaporator and absorber show the highest exergy destruction.
• Power unit exergetic and exergoeconomic costs are reduced with higher hydrogen use.
• Power unit exergetic and exergoeconomic costs are reduced with increasing load.

The thermoeconomic assessment of a cogeneration application that uses a reciprocating diesel engine and an ammonia–water absorption refrigeration system for electrical power and cold production from hydrogen as fuel is presented. The purpose of the assessment is to get both exergetic and exergoeconomic costs of the cogeneration plant products at different load conditions and concentrations of hydrogen–diesel oil blends. The exhaust gas of the reciprocating diesel engine is used as an energy source for an ammonia–water absorption refrigeration system. The reciprocating diesel engine was simulated using the Gate Cycle™ software, and the ammonia–water absorption refrigeration system simulation and the thermoeconomic assessment were carried out using the Engineering Equation Solver software (EES). The results show that engine combustion is the process of higher exergy destruction in the cogeneration system. Increased hydrogen concentration in the fuel increases the system exergetic efficiency for all load conditions. Exergy destruction in the components of the ammonia–water absorption refrigeration system is increased with increasing load due to the rise of heat transfer. At intermediate and high loads energy efficiency is increased in the power system, and low values of unit exergetic cost and competitive specific exergoeconomic costs are noticed. The cogeneration system operation at intermediate and high engine loads was proven to be feasible.