Thermal analysis and optimization of an ice and snow melting system using geothermy by super-long flexible heat pipes. (5th February 2017)

• Record Type: Journal Article
• Authors: Wang, Xiaoyuan; Zhu, Yalu; Zhu, Minzhao; Zhu, Yuezhao; Fan, Hongtu; Wang, Yinfeng
• Is Part Of: Applied thermal engineering. Volume 112(2017:Feb.)
• Page Start: 1353
• Page End: 1363
• Publication Date: 2017-02-05
• Subjects: Ice and snow melting -- Super-long flexible heat pipe -- Heat transfer limit -- Thermal resistance model -- Filling ratio -- Geothermy; Heat engineering -- Periodicals; Heating -- Equipment and supplies -- Periodicals; Periodicals; 621.40205
• DOI: 10.1016/j.applthermaleng.2016.11.007
• Languages: English
• ISSNs: 1359-4311

Abstract

Highlights: An ice and snow melting system via super-long flexible heat pipes is proposed. These heat pipes are designed based on thermally conductive polymer. Thermal analysis is carried out by numerical methods for this system. A thermal resistance model and a filling ratio model are established. Suggested optimization parameters on structure and arrangement are given. Abstract: An ice and snow melting system (ISMS) using shallow geothermy by super-long flexible heat pipes (SFHPs) was originally proposed. SFHPs were designed with thermally conductive polymer (TCP) intending to reduce cost and make it more conveniently to be fabricated, transported, and installed. Thermal analysis and optimization were carried out assuming ISMS is built in Nanjing city, a typical area with roasting summer and freezing winter. Results revealed that ammonia is counted as an optimal working fluid for SFHPs and the recommended dimensions of an SFHP are ∅32 × 2 mm in diameter and 70 m in total length. In addition, there is no need to upgrade the conductivity of TCP to a superior degree. High density polyethylene (HDPE) reinforced by 20% conductive filler content is selected as the pipe base material of SFHP, providing a suitable conductivity of 1.0 W/(m °C) and simultaneously maintaining a well mechanical performance. Furthermore, results show that the appropriate filling ratio for SFHPs ranges from 62% to 65%, and the heat throughput of a single SFHP at steady state is in the range of 850–1200 W varying with climatic conditions. This work will provide a comprehensive guidance to the design and application of ISMS using SFHPs heated by shallow geothermal energy.