Novel evaporator architecture with entrance-length crossflow-paths for supercritical Organic Rankine Cycles

Journal Article · Sun Nov 26 00:00:00 EST 2017 · International Journal of Heat and Mass Transfer

DOI:https://doi.org/10.1016/j.ijheatmasstransfer.2017.11.042· OSTI ID:1423115

Sabau, Adrian S.  ^[1]; Nejad, Ali H. ^[2]; Klett, James W.  ^[1]; Bejan, Adrian ^[3]; Ekici, Kivanc ^[2]

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1. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Materials Science & Technology Division
2. Univ. of Tennessee, Knoxville, TN (United States). Mechanical, Aerospace and Biomedical Engineering Dept.
3. Duke Univ., Durham, NC (United States). Mechanical Engineering and Materials Science Dept.

Here in this article, a novel geometry is proposed for evaporators that are used in Supercritical Organic Rankine Cycles. The proposed geometry consists of successive plenums at several length-scale levels, creating a multi-scale heat exchanger (HX). The channels at the lowest length-scale levels were considered to have their length determined by the thermal entrance-length. Numerical simulations based on turbulent flow correlations for supercritical R134a and water were used to evaluate the performance of heat exchangers. Using the data on pumping power and area of heat exchange, the total present cost was evaluated using a cost model for shell-and-tube heat exchangers. With respect to the shell-and-tube baseline case, the cost per heat load and total costs of new HXs is lowered by approximately 20–26% and 15–30%, respectively. This reduction in present costs of the new HXs were found to be attributed to higher operational costs for the shell-and-tube HXs, as evidenced by the higher pumping power, as well their capital investment costs. The cost savings in the new HX designs compared to those of the shell-and-tube HXs, at similar heat load performance, indicate that the new HX architectures proposed in this paper are valid alternatives to traditional HX designs.

• Research Organization: Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
• Sponsoring Organization: USDOE Office of Energy Efficiency and Renewable Energy (EERE), Renewable Power Office. Geothermal Technologies Office
• Grant/Contract Number: AC05-00OR22725
• OSTI ID: 1423115
• Alternate ID(s): OSTI ID: 1564476
• Journal Information: International Journal of Heat and Mass Transfer, Vol. 119, Issue C; ISSN 0017-9310
• Publisher: Elsevier
• Country of Publication: United States
• Language: English

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