Modeling and Simulation of a Direct Heat Recovery System for Cabin Heating in Battery-Powered Mobile Machines

Abstract

The transition from internal combustion engines toalternative technologies—such as battery-electricpowertrains—in mobile machinery places increased demands onthermal management systems. Cooling requirements below theambient temperature during the summer, and intensiveheating requirements during the winter, lead to holisticbut complex integrated solutions where energy efficiency isof high priority. Research into integrated system solutionsincluding heat pumps and waste-heat recovery has beencarried out mainly on passenger cars. In this study, mobilemachines are considered, and an articulatedexcavator-loader—also known as backhoe loader—is used as anexample. Apart from operating tasks, times, and conditions,the system architecture under the hood differs fromarchitectures usually found in passenger cars, includingworking hydraulic systems. During the early stages ofvehicle development, modeling and simulation of integratedthermal management systems are crucial forproof-of-concept, developing control strategies, andunderstanding subsystem interactions. These processes relyon data that would otherwise require testing on a completevehicle. This paper presents a model of a heat recoverysystem for cabin heating using the DLR Thermofluid StreamModelica library, together with input data from previousresearch based on experiments on a series-hybrid electricmachine. The study investigates the initial feasibility andperformance of a direct heat recovery system for thearchitecture of a battery-powered mobile machine. Theresults show that a simple system design can provide astrong foundation for cabin heating under many of thestudied excavating conditions, though it does not fullymatch the performance of the reference system, which issupplied with heat from an internal combustion engine.