This has been recently published in Applied Thermal Engineering
Comparison of Tubeside Condensation and Evaporation Characteristics of Smooth and Enhanced Heat Transfer 1EHT Tubes
David J. Kukulka*, Rick Smith, Wei Li
Results are presented here from an experimental investigation that was performed to evaluate the inside condensation and evaporation heat transfer of R410A, R22 and R32 that took place in a 12.7 mm (0.5 in) O.D. horizontal copper tube at low mass fluxes. Tubes considered in this evaluation consisted of a smooth tube (inner diameter 11.43 mm) and a newly developed enhanced surface Vipertex™ 1EHT tube. Heat transfer enhancement is an important factor in obtaining energy efficiency improvements in a variety of heat transfer applications. Utilization of enhanced heat transfer tubes is often utilized in the development of high performance air conditioning and refrigeration systems. Vipertex™ has designed and produced these surfaces through three dimensional material surface modifications which produces flow optimized, enhanced heat transfer tubes that increase heat transfer. Heat transfer enhancement plays an important role in improving energy efficiencies and developing high performance thermal systems. This study details the evaluation of the in-tube evaporation and condensation that takes place in these tubes over a wide range of conditions.
The test apparatus utilized included a straight horizontal test section with an active length heated by water circulated in the surrounding annulus. Constant heat flux was maintained and refrigerant quality varied. In-tube evaporation measurements of R22, R32 and R410A are reported for evaporation at 10 OC with mass flow rates in the range of 15 to 40 kg/h. Single phase measurements are reported for mass flow rates from 15 kg/h to 80 kg/h. Condensation tests were conducted at a saturation temperature of 47OC, with an inlet quality of 0.8 and an outlet quality of 0.1. In a comparison to smooth tubes, the average heat transfer coefficients for the Vipertex 1EHT tube exceeded those of a smooth tube. Average evaporation and condensation heat transfer coefficients for R22, R32 and R410A in the 1EHT tube are approximately two times greater than those of a smooth tube.
Enhanced heat transfer tubes are important options to be considered in the design of high efficiency systems. A wide variety of industrial processes involve the transfer of heat energy during phase change. Many of those processes employ old technology; this makes those processes ideal candidates for a redesign using enhanced surfaces that would produce improved process performance. Vipertex 1EHT enhanced tubes recover more energy and provide an opportunity to advance the design of many heat transfer products.
Keywords: Enhanced Heat Transfer Surfaces, Enhanced Tubes, Condensation, Evaporation, Three Dimensional Heat Transfer Surfaces
As we continue to grow our business and our team within Vipertex, we want to be sure we are always bringing you the most up-to-date information on our products, testing, services and solutions. That said, you may have noticed the redirect of our website to now reside within our parent company, Rigidized Metals Corporation.
In the coming weeks and months, we plan to bring you an updated, more informative website with an even wider range of offerings and services that our products can provide. We thank you for your patience!
Presentation of recent condensation and evaporation heat transfer tests have been presented in a keynote paper at PRES14 and CHISA on August 26, 2014 in Prague. The paper has also been published in Chemical Engineering Transactions .
Results are presented here from an experimental investigation of two phase heat transfer that took place in a 12.7 mm (0.5 in) O.D. horizontal copper tube. The test apparatus included a horizontal, straight test section with an active length heated by water circulated in a surrounding annulus. Constant heat flux was maintained and refrigerant quality varied. In-tube evaporation measurements of R22 and R410A are reported for evaporation at 10 °C with mass flow rates in the range of 15 to 40 kg/h. Single phase measurements are reported for mass flow rates from 15 kg/h to 80 kg/h. Condensation tests were conducted at a 47 deg C saturation temperature, with an inlet quality of 0.8 and an outlet quality of 0.1. In a comparison to smooth tubes, the local and average heat transfer coefficients for the Vipertex 1EHT tube exceeded those of a smooth tube. Average evaporation and condensation heat transfer coefficients for R22 and R410A in the Vipertex 1EHT tube are approximately two times greater than those of a smooth tube.
Presentation by Chuck Hogan on the “Use of Vipertex 1EHT Tubes in Fouling Environments” . This will take place at AmeriTAC 113 in Ft. Worth, TX ; sponsored by the Materials Technology Institute on Feb 25 2014.
The article “Development of Vipertex EHT Solar Surfaces for Enhanced Energy Transfer Applications” has been published on Taylor & Francis Online. It is available at: http://www.tandfonline.com/doi/full/10.1080/01457632.2013.837366.
Development of Vipertex EHT Solar Surfaces for Enhanced Energy Transfer Applications
CHEMICAL ENGINEERING TRANSACTIONS – VOL.35
Guest Editors: Petar Varbanov, Jirí Jaromír Klemeš, Panos Seferlis, Athanasios I. Papadopoulos, Spyros Voutetakis
Copyright © 2013, AIDIC Servizi S.r.l.,
ISBN 978-88-95608-26-6; ISSN 1974-9791
|Evaluation of a 1eht Enhanced Heat Transfer Tube Bundle for Processes Involving Boiling||451|
|Kukulka D., Smith R.||>DOI: 10.3303/CET1335075|
Presentation of heat transfer enhancement results for 1EHT bundle boiling over a wide range of conditions is being presented on October 1, 2013 at PRES’ 13 – the 16th Conference on Process Integration, Modelling and Optimisation for Energy Saving and Pollution Reduction.
Results for the 1EHT bundle show combined overall bundle increases of shellside and tubeside heat transfer up to 97% when compared to the heat transfer enhancement of a smooth tube bundle using typical fluids ( n-Pentane, p-Xylene and water); for midpoint shellside Reynolds number values in the range of 2800 to 20400; with effective mean temperature difference (EMTD) values between 15.4 OF ( -9.2 OC) and 118.3 OF ( 47.9 OC). Enhanced heat transfer tube bundles that are capable of producing efficiency increases in excess of 90% are important options to be considered in the design of high efficiency processes.
If you are at Powergen stop at the Vipertex booth (#2080) to see some of our new enhanced heat transfer tubes.
Powergen is at the Orange County Convention Center in Orlando from November 12 to 14 .
Details of the study titled “Evaluation of a 1EHT Enhanced Heat Transfer Tube Bundle for Processes Involving Boiling ” will be presented at 6th Conference Process Integration, Modelling and Optimization for Energy Saving and Pollution Reduction and published in Chemical Engineering Transactions, Vol. 35, 2013.
Utilization of enhanced heat transfer tubes is an effective method used in the development of high performance thermal systems. Vipertex™ enhanced surfaces, have been designed and produced through material surface modifications, which result in flow optimized heat transfer tubes that increase heat transfer.