Transcritical Dual-Loop Organic Rankine Cycle Waste Heat Recovery System for China Vi Emission Standards Natural Gas Engine

Abstract

Natural gas engines have received a great deal of attention because of their high reserves, environmental friendliness and low price. In this paper, a heat balance experiment is carried out for a China VI natural gas engine under external characteristics. In addition, a transcritical dual-loop organic Rankine cycle system is designed to recover the waste heat energy and cool the China VI natural gas engine to improve its reliability. The double-loop organic Rankine cycle system consists of a high-temperature loop and a low-temperature loop coupled by an intermediate heat exchanger. The high-temperature loop uses water to recover exhaust and recirculation exhaust waste heat. The low-temperature loop uses organic working fluids to recover the coolant waste heat and the high-temperature loop waste heat. Water/R32 is the best working fluid combination in this study. After the addition of the organic Rankine cycle, the power of the China VI natural gas engine increases by approximately 71.29 kW at rated conditions, equivalent to 21.03% of the original.

Keywords: Dual-loop Organic Rankine cycle, Waste heat recovery, Natural gas engine, Waste heat characteristics