Deniz taşıtlarında organik Rankine çevrimi (ORC) sistemi uygulaması

The coexistence of different kinds of waste heat sources on marine vessels with various temperature ranges increases the need for an optimal heat exchanger network (HEN) design for the heat collection process to reduce the unutilized heat that needs to be discharged overboard. The optimal HEN design has not been taken into consideration by using pinch point analysis in previous studies of marine organic Rankine cycle (ORC) systems that utilize different kinds of waste heat sources. The first objective of this thesis is to determine the optimal HEN design for an ORC integrated waste heat recovery system (WHRS) of a reference container ship by utilizing the pinch point analysis to improve the overall energy efficiency. The availability and potential use of cargo oil pump turbine (COPT) based waste heat offer more feasible solutions for ORC utilization to tanker ships. The second objective of the thesis is to introduce a new WHRS design for tanker ships that can utilize both marine diesel engines waste heat during navigation and COPT based waste heat during cargo discharge operations in ports. As a case study, the waste heat sources of a reference oil tanker vessel were identified and the thermodynamic analyses were carried out. The last objective is to attain exergetic sustainability indicators for both cases to assist decision-making processes that consist of decisions of implementing the proposed system design and which performance parameters should be used to achieve a better sustainability performance. The results indicate that all the waste heat cannot be collected by thermal oil, as some of the waste heat needs to be discharged through the sea. The most efficient and most sustainable working fluids among the selected alternatives are found as R1234ze(Z) at higher evaporating pressures than 1.4 MPa for container ship case, and R1233zd(E) for tanker ship case. The COPT based waste heat recovery potential is found as almost 3.5 times higher at full load operation of three COPTs than waste heat recovery potential of the main engine at full load navigation.