01.2020.171.179

HEAT TRANSFER PERFOMANCE OF UNDERGROUND U-TYPE HEAT EXCHANGER: A CFD MODEL-BASED ANALYSIS

Author(s):
Van Hien Ngo†, Kieu Hiep Le‡*, Gia Diem Pham†, Van He Ngo†, Tien Anh Nguyen‡, Quoc Bao Nguyen‡, Tien Cong Do‡, Quyet Hung Vu‡, & Van Thuan Nguyen‡

Affiliation(s):
†School of Transportation Engineering, Hanoi University of Science and Technology, 01 – Dai Co Viet, Hai Ba Trung, Hanoi, Vietnam

‡School of Heat Engineering and Refrigeration, Hanoi University of Science and Technology, 01 – Dai Co Viet, Hai Ba Trung, Hanoi, Vietnam

*Corresponding Author Email: hiep.lekieu@hust.edu.vn

This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

In this work, a ground heat source cooling system is proposed for cooling of a base transceiver station (BTS), instead of traditional air conditioner with compressor. This cooling system is comprised of a vertical underground heat exchanger, a fan coil unit and a circulating pump. Liquid water enters the fan coil unit to be heated up by adsorbing the heat load of BTS and flows into the underground heat exchanger. In the underground heat exchanger, water released the thermal energy to the surrounding soil. To design the underground heat exchanger, the heat transfer coefficient between water and soil is required as an essential input. In this work, a CFD model of underground U-type heat exchanger has been developed. The influence of computational domain size, mesh resolution on the numerical results are checked. Based on the temperature distribution along the water tube, the heat load and overall thermal resistance are determined. The impact of tube diameter, vertical tube length, water inlet temperature and velocity, soil thermal conductivity on the overall thermal resistance are investigated.