BUILDING A TECHNOLOGICAL MODEL OF THE EXHAUST GAS ENERGY RECOVERY DEVICE FOR THE DIESEL ENGINE ON A SMALL­SIZED VESSEL

Recuperation systems that utilize the energy of exhaust gases from existing diesel engines are designed for large and medium-sized vessels. There is a need to develop an appropriate system to recover the energy of exhaust gases for small-sized vessels. We have designed a technological model of the recuperation device for small vessels in the form of a thermoelectric generator (TEG) that operates on the exhaust gas energy. Technical conditions for the TEG arrangement on a vessel have been analyzed and the components of its design have been defined. We have proposed technical solutions for improving the process of energy heat transfer from gas to a TEG, namely: the use of thermoelectric modules (TEM) with an operating temperature above 1,000 °С; the application of a square shape of the pipeline cross-section, and the arrangement of a spiral-type cylinder inside the generator pipeline. Based on the theoretical calculations, we have examined a thermal model of the thermoelectric generator and estimated the technological parameters for using TEM in order to ensure maximum value of efficiency for a TEG. The need to divide the generator into three constituent sections has been identified, which operate as separate generators. We have shown a possibility to receive up to 0.8 kW of electric energy when using a TEG provided the rotation speed of the diesel engine shaft is 1,500 rpm. An optimal technique for utilizing the generator electric energy has been proposed, which implies the application of a motor-wheel. A motor-wheel function is to transform the excess electrical energy from a TEG into mechanical energy (to support the main engine) within a comprehensive increase in the fuel utilization efficiency. An appropriate circuit to connect a motor-wheel to the vessel's power system has been given. We have identified ways to improve the efficiency of a thermoelectric generator and extend the scope of its application on small vessel