Optimum composition ratios of multicomponent mixtures of organic Rankine cycle for engine waste heat recovery

Abstract

With the temperature glide in saturation states, the mixture working fluids have the advantages in thermal energy conversion. In this study, through the investigation in optimum mass fractions of multicomponent mixture working fluids, the economic performance enhancement of the organic Rankine cycle system is obtained for recovering waste heat from engine. The zero ozonedepletion-potential and dry working fluids of R236fa, R245fa, and R1336mzz (Z) are selected as the components of multicomponent mixtures in the system. The net power output, heat transfer calculation, and apparatus cost evaluation are employed to evaluate the power cost of the organic Rankine cycle system. Parameters of temperatures of waste heat sources and efficiencies of expanders are taken into account. The comparisons of economic performances for singlecomponent working fluid and multicomponent mixtures with optimum mass fractions are proposed. The results show that R245fa, having a levelized cost of energy, LCOE, of 8.75 × 10 −2 $/kW-h, performs the best for single-component working fluids, better than R236fa by 1.6% and R1336mzz(Z) by 8.3%. All the two-component mixtures are superior to their single-component working fluids in economic performance. Among the three two-component mixture working fluids, R1336mzz(Z)/R236fa has the lowest LCOE min , 8.57 × 10 −2$/kW-h, followed by R236fa/R245fa and R245fa/R1336mzz(Z). In addition, R236fa/R245fa/R1336mzz(Z) mixture, which has a LCOE min of 8.47 × 10 −2 $/kW-h, economically outperforms all other working fluids and has a lower LCOE min than R236fa/R245fa by 1.7% and R245fa/R1336mzz(Z) by 2%. K E Y W O R D Scomposition ratio, economic performance, multicomponent mixture, organic rankine cycle, working fluid

Techno-economic feasibility analysis of zeotropic mixtures and pure fluids for organic Rankine cycle systems

“…The conclusions from the research papers highlighted above, show cases where zeotropic mixtures were found to be the more economically feasible working fluids [11,12,[15][16][17][18][19][20]22], whereas other papers indicate that pure fluids are more beneficial [13,23,24,[26][27][28]31].…”

“…Yang and Yeh [22] investigated the economic performance of mixtures of R236fa, R245fa, and R1336mzz(Z) and found that the lowest levelized cost of electricity among the considered two-component mixtures and pure fluids is obtained for the mixture R1336mzz(Z)/R236fa. The papers addressing ORC units for waste heat recovery mentioned above indicate that it can be economically feasible to utilize zeotropic mixtures as working fluids.…”

“…The literature review indicates that the use of hydrofluoroolefin (HFO) fluids in mixtures result in higher economic performance compared to pure fluids in waste heat recovery applications [15,20,22]. However there is a lack of studies evaluating the techno-economic feasibility of mixtures including HFOs for ORC units tailored for geothermal applications.…”

An effective and simplified method to select the working fluid for waste heat recovery based Organic Rankine Cycle

“…Freeman et al [21] has examined the potential of power generation using ORC run through combined heat and power scheme and reported that system is able to produce 1070 kW h yr-1 of electricity with 6.3% efficiency. There are some other research groups [11], [22,23,24,25] who have analyzed the ORC as a waste heat recovery system and reported the ORC is best suited for the utilization of low-grade waste heat. Lim et al From the above discussions, one can conclude that ORC is the best option to capture the low-grade heat and utilize waste heat.…”

Pre‐adsorption of low‐grade waste steam for high‐temperature steam generation by using composite zeolite and long‐term heat storage salt of MgSO 4

“…Industrial waste heat recovery technologies can be classified as active technologies and passive technologies . The active technologies including mechanical vapor compressor, sorption heat pump/chiller, and Organic Rankine Cycle reuse the waste heat to achieve heating, cooling, or power generation purpose. The passive technologies consist of heat exchanger and Thermal Energy Storage technologies which directly recovery the waste heat at the same or at lower temperature level.…”