Investigation of the Effect of the Regenerative Heat Exchanger on the Performance of Organic Rankine Cycles Using Perturbed Chain–Statistical Associating Fluid Theory Equation of State

Abstract

In the following study, two of the most commonly used and analyzed organic Rankine cycles (ORC), one with a basic set and another one with a regenerative heat exchanger, are investigated at different temperature levels below 450 K. The work involved implementing the continuous-molecular targeting approach to computer-aided molecular design in an optimization procedure using thermodynamic modeling software for generating the different ORC configurations. After finding the optimal operating parameters and ideal working fluid for each temperature range with a genetic algorithm, the performances of the cycles are compared. The results show that the most frequently investigated setup when the cycle is extended with a regenerative heat exchanger is not necessarily superior over the basic ORC. Under certain conditions, the simpler and more affordable design could lead to higher performance. Therefore, a thorough examination requires the investigation of both topologies. Also, groups of substances that may become fourth-generation refrigerants in the future due to zero ODP and low GWP were also examined.

Analysis of the Maximum Efficiency and the Maximum Net Power as Objective Functions for Organic Rankine Cycles Optimization

“…However, in the neighborhood of the critical point of the fluid, the gap evolves smaller, but it does not vanish. Figure 5 also displays a temperature range from 360.00 K up to 480.00 K, which matches the temperature range corresponding to the applications from low and moderate temperature sources, such as the geothermal, solar, and residual energy [ 9 , 40 ]. As indicated in Figure 5 , each working fluid has a range of temperature depending on the condenser temperature, where the boiler’s operating temperature can move.…”

The Use of Organic Rankine Cycles for Recovering the Heat Lost in the Compression Area of a Cryogenic Air Separation Unit

“…The high destruction of exergy in the vaporizer led to the introduction of an internal recuperative heat exchanger [ 34 ]. The primary goal was to increase the mechanical power under conditions of a steadily recovered heat flux.…”

Thermoeconomic Optimization Design of the ORC System Installed on a Light-Duty Vehicle for Waste Heat Recovery from Exhaust Heat

“…Both isentropic efficiencies are chosen based on the published papers, which show that the isentropic efficiency of the pump and expander are, respectively, in the ranges of 7% to 60% [29][30][31] and 26% to 73.4% [29,32,33]. The selection of working fluids for waste heat recovery based on ORC has been investigated by numerous studies [24,34,35]. In this paper, our work focuses on proposing an ORC thermal-economic optimization method that considers the negative impact of the ORC installation and validates the obtained optimization results under drastic changes in exhaust heat conditions of a light-duty vehicle.…”

“…To study the effect of working fluids with different critical temperatures on the results of thermal-economic optimization, four working fluids with different critical temperatures were selected from the available literature [32,33] and are listed in Table 2. In general, the category of working fluid affects the design of an ORC [34]. If the sensible heat after the expansion of the working fluid is reused through the recuperator, the heat load of the condenser decreases, and correspondingly, the condensation consumption of the condenser is reduced.…”