Predicting the Slope of the Temperature–Entropy Vapor Saturation Curve for Working Fluid Selection Based on Lee–Kesler Modeling

Journal Article · Wed Dec 18 00:00:00 EST 2019 · Industrial and Engineering Chemistry Research

DOI:https://doi.org/10.1021/acs.iecr.9b05736· OSTI ID:1592085

Rivera-Alvarez, Alejandro ^[1]; Abakporo, Obie I. ^[2]; Ordonez, Juan C ^[3]; Osorio Ramirez, Julian  ^[4]; Hovsapian, Rob ^[4]

---

1. Ingeniería Termica Ltda., Medellín ( Colombia); Fundacion Ergon, Medellín (Colombia)
2. Florida A & M University, Tallahassee, FL (United States)
3. Florida State Univ., Tallahassee, FL (United States)
4. National Renewable Energy Lab. (NREL), Golden, CO (United States)

This paper presents a general, novel, and accurate method to determine the shape of the temperature-entropy (T-S) vapor saturation curve for fluids, based on Lee-Kesler's version of the corresponding states principle. The slope of the T-S vapor saturation curve and the location of isentropic points are successfully predicted for any fluid as a function of only three input variables: acentric factor (..omega..), ideal-gas ratio of specific heats at the critical temperature (k_c), and the exponent of the heat capacity ratio vs temperature power relationship (m). The proposed method is then applied to a set of 120 commercially available fluids, and the results are validated with experimental data. As the method effectively distinguishes among dry, wet, and isentropic fluids, a simple semiempirical equation establishing the frontier between wet and dry fluid regions is discovered. The developed method can be used as an effective tool for working fluid selection for organic Rankine cycles (ORCs), refrigeration cycles, and heat pumps. It also has the potential to aid the development of new fluids with a proper set of characteristics for specific applications.

• Research Organization: National Renewable Energy Lab. (NREL), Golden, CO (United States)
• Sponsoring Organization: USDOE Office of Energy Efficiency and Renewable Energy (EERE)
• Grant/Contract Number: AC36-08GO28308
• OSTI ID: 1592085
• Report Number(s): NREL/JA-5500-75160; MainId:14990; UUID:429fc48e-97eb-e911-9c29-ac162d87dfe5; MainAdminID:3468
• Journal Information: Industrial and Engineering Chemistry Research, Vol. 59, Issue 2; ISSN 0888-5885
• Publisher: American Chemical Society (ACS)
• Country of Publication: United States
• Language: English

Related Subjects

42 ENGINEERING
temperature-entropy saturation curve
corresponding states
Lee-Kesler modeling
wet, dry, and isentropic fluids
working fluid selection.