Thermo-economic Review of Micro-scale Organic Rankine Cycle Integrated into Vehicle Engines for Waste Heat Recovery

抄録

Heavy-duty diesel engines have been widely applied in commercial vehicles. However, escalating consumption of fossil fuels and stringent legislation of CO₂ emission have raised the concern about searching for viable technologies to improve the fuel energy efficiency recently. Generally, optimization technology of engines can be categorized into two types: engine-powertrain-applied and engine-bottoming cycles. The bottoming organic Rankine cycle is an applicable combined heat and power (CHP) technology with great potential for engine waste heat recovery. The aim is to increase the fuel energy efficiency without additional fuel consumption. In this paper, a thermo-economic overview of organic Rankine cycle system integrated into engines especially for on-the-road vehicle is presented. First of all, characteristics of various engine waste heat (e.g. exhaust gas, EGR, CAC, jacket cooling water, oil circuit) are briefly analyzed; Afterwards, special attention is paid to the screening criteria of appropriate expansion machine and working fluid selection; Subsequently, an overview of various layout of organic Rankine cycle was presented; Eventually, cost-orient economic evaluation of the synthesis cycle is overviewed, which is meant for characterizing the optimum system design.