Techno-economic Optimization of ORC for Gas Engine Waste Heat Recovery

In this paper organic Rankine cycle (ORC) was introduced for gas engine waste heat recovery. The ORC system plan to build in National Energy Distributed Energy Technology R&D Center, use two 315kW MJI GS6R2-PTK gas engine jacket water as heat source. The components' model and economic model for ORC system were established. Then 20kW ORC system was designed and optimized by fast and elitist multi-objective genetic algorithm (NSGA II). Both system efficiency and total cost were optimized during the design process. The optimization results show ORC system without recuperator is more profitable for commercial applications. Besides ORC system tend to operate with lower superheating temperature.

I. Introduction

With the increasing energy demand, rising energy prices and a series of environmental problems such as global warming, we are forced to seek cleaner and sustainable energy[1]. It is a promising method to convert waste heat energy into electricity[2]. It is reported that more than half of the energy generated by various renewable and nonrenewable resources in the world is discharged into the environment, mainly waste heat. There are huge reserves of such heat energy around the world, releasing thousands of joules of energy into the ambient atmosphere per second. The undisputed way to recycle and utilization heat from waste energy can be completely changed by using natural energy.