مدلسازی عددی و بررسی تاثیر جریان آب زیرزمینی سطحی و همرفت طبیعی بر توان خروجی شمع انرژی

نوع مقاله : مقاله پژوهشی

نویسندگان

1 دانشکده مهندسی عمران ، دانشگاه تربیت مدرس، تهران، ایران.

2 دانشکده مهندسی عمران، دانشگاه صنعتی شریف، تهران، ایران

چکیده

در سال‌های اخیر استفاده از انرژی‌‌های تجدید پذیر بخصوص انرژی زمین گرمایی کم عمق برای گرمایش و سرمایش مکان‌‌های مختلف در فصل‌های گرم و سرد سال بسیار مورد توجه قرار گرفته‌است. از این رو بررسی عوامل طبیعی تاثیرگذار بر کارایی این سیستم، به ویژه جریان آب زیرزمینی دارای اهمیت خاصی است به نحوی که مشخص شده‌است وجود جریان آب زیرزمینی به طور قابل توجهی باعث بهبود عملکرد سیستم انرژی زمین گرمایی کم عمق ‌‌می‌‌شود. اما بررسی عملکرد این سیستم تحت تاثیر جریان آب زیرزمینی همواره با خطاهایی روبرو بوده است که به آن کمتر پرداخته شده‌است. در این پژوهش، یک شمع انرژی با در نظر گرفتن جریان آب زیرزمینی سطحی و اثر همرفت طبیعی توسط نرم افزارCOMSOL Multiphysics  و روش عددی اجزا محدود، در شرایطی که دمای سطح زمین و سیال ورودی به لوله ثابت است، در یک بازه‌‌ی 90 روزه و با لوله گذاری U شکل مدلسازی شده و مورد مطالعه قرار گرفته‌است. نتایج این بررسی‌‌ها نشان می‌‌دهد که جریان آب زیرزمینی سطحی می‌تواند به علت اختلاف دمای قابل توجه بین سطح و عمق زمین باشد بطور کل تحت تاثیر جریان همرفت طبیعی قرار گیرد که باعث انتقال دمای سطح زمین به درون دامنه خاکی شود و این موضوع باعث کاهش قابل توجه توان خروجی سیستم در فصول سرد و گرم سال به ترتیب به میزان تقریبی 27 و 10 درصد می‌‌گردد. همچنین نحوه تغییرات دما در داخل توده خاکی تحت تاثیر جریان همرفت طبیعی در فصل گرم به صورت یکنواخت در عمق و فصل‌های سرد بصورت نامنظم می‌باشد.

کلیدواژه‌ها

موضوعات


عنوان مقاله [English]

Numerical modeling and analysis of the effect of surface groundwater flow and natural convection on the heat exchange of energy pile

نویسندگان [English]

  • Makan Fattahian 1
  • mohammad Hosain Sobhdam 2
  • Mohammad Mehdi Ahmadi 2
1 MSc, Geotechnical Group, Civil Engineering Faculty, Tarbiat Modares University, Tehran, Iran
2 Professor, Geotechnical Group, Civil Engineering Faculty, Sharif University of Technology, Tehran, Iran
چکیده [English]

The use of renewable energy, particularly shallow geothermal energy, for heating and cooling various spaces during both hot and cold seasons has received considerable attention. Therefore, investigating the natural factors affecting the efficiency of this system, especially the groundwater flow, is of particular importance. The presence of groundwater flow significantly increases the efficiency of shallow geothermal systems. It has been found that the existence of groundwater flow significantly improves the efficiency of the shallow geothermal energy system. However, the assessment of system efficiency under the influence of groundwater flow is often subjected to error and has been inadequately addressed in the literature. In this study, an energy pile was modeled for a period of 90 days using COMSOL Multiphysics software and the finite element method, taking into account surface groundwater flow. The modeling assumes constant soil and inlet fluid temperature. The analysis was carried out for heating and cooling scenarios with various U-shaped pipe existence of groundwater flow. The results indicate that the presence of surface groundwater flow due to natural convection, independent of soil temperature, leads to a significant reduction in system performance.

کلیدواژه‌ها [English]

  • Geothermal Energy - Energy Pile
  • Groundwater Flow - Numerical Modeling
  • Natural Convection
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