کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
5450806 1513068 2017 12 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Comparative study of melting and solidification processes in different configurations of shell and tube high temperature latent heat storage system
ترجمه فارسی عنوان
بررسی مقایسه ای فرایندهای ذوب و خزش در تنظیمات مختلف سیستم ذخیره سازی گرما نهفته با دمای بالا پوسته و لوله
کلمات کلیدی
تغییر فاز مدل سازی، ذخیره سازی گرمایی خنثی، جریان موازی، ذوب، جامد سازی، ضد جریان،
موضوعات مرتبط
مهندسی و علوم پایه مهندسی انرژی انرژی های تجدید پذیر، توسعه پایدار و محیط زیست
چکیده انگلیسی
The performance of parallel and counter flow configurations of a shell and tube heat exchanger used as a latent heat thermal storage system was investigated. The comparative analysis of the melting and solidification processes (charging and discharging) in the vertical and horizontal orientations of counter and parallel flow was included in this study to make the results conclusive for the purpose of design of the storage system to be used in a concentrated solar power (CSP) plant. In this analyses, taking into account natural convection, numerical calculations were performed using ANSYS Fluent. The vertical parallel flow configuration shows 12% higher effectiveness compared to the counter flow for the charging and discharging processes. A higher rate of phase change occurs for both the charging and discharging processes in a parallel flow configuration, as a higher fraction of phase change material (PCM) is exposed to the heat transfer fluid inlet temperature compared to the counter flow. However, a lower temperature gradient and nearly constant effectiveness for a longer period of time are observed in the counter flow arrangement due to the higher rate of natural convection. An interesting result is the higher rate of natural convection in the horizontal orientation compared to the vertical one due to the Benard convection phenomenon, despite the fact that Ra is higher in the vertical orientations (1010 > 107). The horizontal counter flow and parallel flow configurations show on average 10% higher effectiveness for the charging process which is constant for a longer period during the process compared to the vertical configurations whereas the horizontal arrangement during the discharging process improves the effectiveness by about 2% due to the minor role of natural convection. The horizontal configurations provide a more uniform phase change process with the lowest peak temperatures (in the melting processes) and temperature gradient which are correlated with the highest second law efficiency and exergy recovery.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Solar Energy - Volume 150, 1 July 2017, Pages 363-374
نویسندگان
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