A Review of the Scientific Literature for Supercritical CO2 Applications to Propose its Efficacy as a Heat Transfer Fluid and for Vapor Compression Cycles

J.C. Zelaya, A. Tremante
Florida International University,
United States

Keywords: super-critical carbon dioxide, vapor compression cycles, sco2 applications, sco2 power cycles

Summary:

In recent years supercritical carbon dioxide has gained popularity in the scientific and industrial communities for its superb thermophysical properties including, but not limited to, heat transfer ability. This paper aims to review the many applications of SCO2 with a focus on the substance used as a heat transfer fluid and efficacy in vapor compression cycles. Though primarily a supercritical fluid used in the extraction of many substances, SCO2 has vast applications as a working fluid in various power cycles. Brayton and Organic Rankine Cycle studies show the use of supercritical carbon dioxide as a means of increasing overall thermal efficiency by as much as 3% in certain cases. These entries also propose comprising the cycles of a much simpler set up than traditional ones. As a heat transfer fluid, dozens of studies from various journals propose excellent heat transfer correlations which aid to track down the application of flow through various means and channels. Specifically, the work of Ehsan, Guan & Klimenko for the “Journal of Renewable and Sustainable Energy Reviews”, compile a large magnitude of data from their comprehensive review regarding heat transfer and pressure drop characteristics of SCO2. The resulting data introduces the ability to manipulate the fluid to the advantage of the application at hand. Again, the true focus of this paper lies in the breakdown of the scientific literature regarding various stages and components of the vapor compression cycles. In turn, the hopes of this review are to provide insight into the efficacy of the use of SCO2 in such a system. Compressor, condenser, expansion valve and capillary tube as well as evaporator focused studies are examined and considered to prove the efficacy of an SCO2 Vapor-Compression cycle. These studies have been thoroughly analyzed, they include within them an array of novel and computational-experimental set ups to provide enough theory and data. Included as well is a discussion of the setbacks of supercritical carbon dioxide which involve the high-pressure problem and material corrosion. Finally, a call for carbon sequestration and environmental impact is briefly discussed as well as a call to action for further investigation into the subject matter.