Study on the effect of heat exchange tube structure on waste heat recovery capacity of the internal combustion engine in the freshwater distillation system

Abstract

In the Internal Combustion Engine (ICE) working operation, fuel is fed into the combustion chamber, where it is burnt in air to convert the chemical energy of fuel into heat according to the first law of thermodynamics. However, the amount of energy transformed into actual power is only 21-33% and 25-40% for gasoline engines and diesel engines, respectively. Consequently, about two-thirds of the remaining energy is lost due to the heat transfer to the surrounding environment, in which the heat energy removed by the exhaust occupies the largest proportion (about 30-35%). Therefore, utilizing the regenerative heat from the exhaust gases is a potential solution to improve the ICE’s efficiency. This paper presents the simulation results of the effect of heat exchange tube structure on waste recovery capacity in the system, which utilizes the heat of exhaust gases and cooling water of ICE based on Ansys Fluent. In addition, the boundary conditions, the flow, and exhaust temperature are determined by simulating the engine’s working process using AVL-Boost. This research shows that the heat utilization efficiency of exhaust energy can be achieved up to 34%, corresponding to a reasonable structure. This research’s study outcomes are the foundation to implement the complete design of the heat waste recovery system of ICE.