Simulation research of TEG-ORC combined cycle for cascade recovery of vessel waste heat

Abstract

ABSTRACT The waste heat of ships has the characteristics of large temperature gradient, huge recoverable amount and various properties. Traditional technologies such as thermoelectric power generation (TEG) and organic Rankine cycle (ORC) are difficult to take into account the different characteristics of the various types of waste heat from ships. In order to realize the efficient cascade utilization of various waste heat from ships, improve the efficiency and meet the stringent requirements of the new international carbon emission regulations, a cascade recovery system of ship waste heat based on TEG-ORC (thermoelectric power generation/organic Rankine cycle) is proposed in this paper. After designing of the TEG-ORC combined cycle experimental system, the simulation research has also been carried out. The effects of TEG bottom cycle scale, ORC working medium flow rate and evaporation pressure on system net output power, system power generation cost and bottom cycle ratio (QTEG/QORC ) are studied. The results show that the TEG-ORC combined cycle overcomes the limitation of single waste heat utilization method, realizes multi-stage utilization of ship waste heat, as well as improves the utilization of waste heat. Of course, the stability and safety of ORC bottom cycle operation are also promoted. The simulation results show that when the TEG bottom cycle scale is 22 pieces, ORC working medium flow rate is 0.44 kg/s, and ORC working medium evaporation pressure is 2.2MPa, the system economy is optimal. At this time, the system power generation cost is 0.26 $/kW·h, the system net output power is 2520.3 W, and the thermal efficiency is 23.33%.