United States Government Publishing Office publisher pbl distributor dst United States Commerce Department National Institute of Standards and Technology (NIST) author aut Government Organization Kedzierski, Mark A. author aut text government publication eng GOVPUB Executive Agency Publications executive 2023-10-27 Commerce Department 2022-04-21 monographic New version deposited born digital 97 digital object pages C 13. https://www.govinfo.gov/app/details/GOVPUB-C13-f28c2ecab214aecf80f5bac173d6806e P0b002ee1c1bb3d65 on1389890364 (OCoLC)1389890364 DGPO 2023-10-27 2026-06-27 GOVPUB-C13-f28c2ecab214aecf80f5bac173d6806e machine generated eng fdlp C13 GOVPUB-C13-f28c2ecab214aecf80f5bac173d6806e f28c2ecab214aecf80f5bac173d6806e GOVPUB NIST Technical Notes NOTE: THE “DATE ISSUED” ABOVE MAY DEFAULT TO JANUARY 1ST OF A GIVEN YEAR. TO THE VIEW THE MOST ACCURATE DATE OF ISSUE, REVIEW THE TITLE PAGE OF THE PUBLICATION. Studies or reports which are complete in themselves but restrictive in their treatment of a subject. Analogous to monographs but not so comprehensive in scope or definitive in treatment of the subject area. Often serve as a vehicle for final reports of work performed at NIST under the sponsorship of other government agencies. National Institute of Standards and Technology Commerce Department. National Institute of Standards and Technology. 2022 2022-04-21 https://www.govinfo.gov/app/details/GOVPUB-C13-f28c2ecab214aecf80f5bac173d6806e https://www.govinfo.gov/content/pkg/GOVPUB-C13-f28c2ecab214aecf80f5bac173d6806e/pdf/GOVPUB-C13-f28c2ecab214aecf80f5bac173d6806e.pdf Extensive Measurement and Analysis Boiling Enhanced heat transfer Low-GWP Micro-fin Refrigerant mixtures Refrigerants Kedzierski, Mark A. creator Kedzierski, Mark A. Kang, Donggyu. National Institute of Standards and Technology (U.S.) Engineering Laboratory mdu U.S. Dept. of Commerce, National Institute of Standards and Technology 2022-04-21. New version monographic 1 online resource (97 pages) : illustrations (black and white) text technical report eng This report presents local convective boiling heat transfer and Fanning friction factor measurements in a micro-fin tube for R134a and two possible low global warming potential (GWP) refrigerant replacements for R134a: R1234yf and R450A. Test section heating was achieved with water in either counterflow or in parallel flow with the test refrigerant to provide for a range of heat fluxes for each thermodynamic quality. An existing correlation from the literature for single and multi-component mixtures was shown to not satisfactorily predict the convective boiling measurements for flow qualities greater than 40 %. Accordingly, a new correlation was developed specifically for the test fluids of this study so that a fair comparison of the heat transfer performance of the low GWP refrigerants to that of R134a could be made. The new correlation was used to compare the heat transfer coefficient of the three test fluids at the same heat flux, saturated refrigerant temperature, and refrigerant mass flux. The resulting example comparison, for the same operating conditions, showed that the heat transfer coefficient of the multi-component R450A and the single-component R1234yf were, on average, 15 % less and 5 % less, respectively, than that of the single-component R134a. Friction factor measurements were also compared to predictions from an existing correlation. A new correlation for the friction factor was developed to provide a more accurate prediction. The measurements and the new models are important for the evaluation of potential low-GWP refrigerants replacements for R134a. Mark A. Kedzierski; Donggyu Kang. April 2022. Title from PDF title page (viewed January 4, 2023). Includes bibliographical references. Approved by the NIST Editorial Review Board on 2022-04-20 Mode of access: World Wide Web. Systems requirements: Adobe Acrobat PDF reader. Refrigerants Boiling Enhanced heat transfer Low-GWP Micro-fin Refrigerant mixtures https://doi.org/10.6028/NIST.TN.1966r1 extensive measurement and analysis extensive measurement and analysis