Investigation of a Dual-Loop ORC for the Waste Heat Recovery of a Marine Main Engine

Abstract

As carbon dioxide emissions arising from fossil energy consumption and fossil fuels are gradually increased, it is important for the low-carbon operation of ships to recover diesel engine waste heat. A newly developed dual-loop organic Rankine cycle (ORC) system to recover waste heat from a marine main engine (M/E) was designed in this paper. The exhaust gas (EG) heat was recovered by the high-temperature (HT) loop. The jacket cooling water (JCW) heat and the condensation heat of the HT loop were recovered by the low-temperature (LT) loop. Toluene, cyclohexane, benzene, R1233zd (E), R245fa, and R227ea were selected as the working fluids. The influence of the condenser thermal parameters on the LT loop was analyzed using the pinch point method. The performance of the dual-loop ORC was investigated under various working fluid combinations. The maximum net power of the HT loop can reach 253.4 kW when using cyclohexane as the working fluid, and the maximum thermal efficiency of the HT loop can reach 18.5% with benzene as the working fluid. Meanwhile, higher condensation temperatures and levels of condensation heat of the HT loop have a positive effect on the performance of the LT loop. However, in most conditions, the HT loop condensation heat could not provide enough heat for the LT loop’s working fluid to start the boiling process. The total net power of the dual-loop ORC system was 410.6 kW with Cyclohexane in the HT loop and R1233zd (E) in the LT loop, resulting in a 10.9% improvement in the marine main engine thermal efficiency.

Optimal Parameter Identification of Single-Sensor Fractional Maximum Power Point Tracker for Thermoelectric Generator

“…The rapid advancement of fossil fuel utilization has resulted in significant environmental consequences, which are evident in abnormal climate change [1,2]. Various methods for controlling climate change have been developed, including: (1) increasing the efficiency of current processes through heat recovery [3,4], especially in energy intensive consuming industries [5,6]; (2) using efficient and environmentally friendly energy conversion devices such as fuel cells [7,8]; (3) and/or relying on sustainable renewable energy sources with low or no environmental impacts [9,10]. In the current stage, waste heat recovery is the most credible solution until commercial renewable energy sources are developed at reasonable prices compared to those of conventional fuels.…”

Thermo-Economic Analysis and Multi-Objective Optimization of a Novel Power Generation System for LNG-Fueled Ships

“…However, the application of this technology has been primarily concentrated in land-based facilities, and there is a notable lack of research specifically tailored for the recovery of waste heat in maritime settings [10]. To address this gap, researchers have begun to turn their attention to this particular area [11][12][13][14].…”

“…To address this issue, scholars have started exploring ways to integrate both waste heat and cold energy. Lyu et al [11] designed a novel dual-loop ORC system that successfully utilized the waste heat from JCW and EG. By employing n-pentane and R125 as the working fluids, the system efficiency was improved, achieving a 5.17% increase in output power.…”