Exploration of LNG cold energy utilization system for LNG-fueled fishing vessels

Liquefied natural gas(LNG) fueled fishing vessels have a wide horizon of development, in order to improve the LNG cold energy utilization efficiency of them, this paper compared the pros and cons of recycling LNG cold energy through refrigerated warehouse and power generation, and proposed a new LNG cold energy utilization system for LNG-fueled fishing vessels. The utilizing efficiency of cold energy and exergy in different Rankine cycle condensation temperature, evaporation temperature and secondary refrigerant outlet temperature were obtained in this paper. The results show that the utilizing efficiency of cold energy increases significantly when Rankine cycle condensation temperature decreases or evaporation temperature rises. As secondary refrigerant outlet temperature increases, the utilizing efficiency of cold energy increases slightly, but the flow rate of secondary refrigerant increases significantly. In this system, the maximum cold energy utilization efficiency and exergy utilizing efficiency can respectively reach 200.1% and 28.6%, improved significantly and energy-saving effect is remarkable.