Pressure drop study on an Organic Rankine System utilizing LNG

Abstract Liquid natural gas (LNG) occupies an important place in global energy market. In 2015, gas occupied 45% of global energy demand driven by increases demand for fuel and power generation [1]. The outlook for LNG usage is positive and continues to gain momentum [2]. This paper studies the pressure drop in an Organic Rankine Cycle (ORC) system used to recover energy from an LNG engine aboard a ship and aims to fill in the gaps of previous research and provide more details of LNG cryogenic energy utilization. The ORC utilizes the temperature difference between the exhaust gas and LNG to generate power. The thermodynamic process is modelled using an Engineering Equation Solver (EES). The calculation of the pressure drop starts with the heat exchangers in the cycle which are modelled as plate heat exchangers for both the evaporator and condenser. The effect of the pressure drops in the heat exchangers on whole system is then studied. The results of the calculation are that the pressure drop decreases the system efficiency and increases with the fluids’ mass flow rate. The difference between the working temperature range of fluids and actual working temperature range will increase the negative influence of the pressure drops.