Feasibility of geothermal heat exchanger pile-based bridge deck snow melting system: A simulation based analysis

Abstract

Snow melting system based on geothermal heat exchanger pile is an innovative technology that combines geothermal energy with structural foundation. It overcomes the problems of conventional chemical based snow melting in mitigating infrastructure corrosion and negative environmental effects. By integrating the underground heat exchanger into pile foundation that support the bridge structure, it effectively reduces the installation cost of geothermal system. This paper analyses the applicability and performance of such snow melting system for different regions. Energy demand for snow removal is firstly determined with ASHRAE criteria. A holistic 3D simulation model is developed to predict the energy extraction rate under different operation conditions. A hypothetical bridge deck (200 m length by 14.8 m (4 lanes) width) is analyzed to assess the feasibility of geothermal heat exchanger pile based snow melting system for 10 cities representing a variety of climatic regions of the United States. The number of pile foundation required for snow melting is used as indication of the technical feasibility. The results show that its feasibility and performance in bridge deck snow removal is dependent upon the geological and snow conditions of a particular region, as well as the design snow removal criteria.

A resistive-capacitive model of pile heat exchangers with an application to thermal response tests interpretation

“…Numerical simulation is also commonly used as a research tool, for example to investigation of pipe arrangements and thermal performance (e.g. [9], [10], [11] , [12] , [13], [14], [15], [16], [17]), but is rarely practical for routine applications.…”

Performance of a geothermal energy deicing system for bridge deck using a pile heat exchanger

“…However, this level of heat flux was much lower than the calculated heat flux, which could keep the slab free from snow (A r = 1) during snowfall according to previous research. 17 Therefore, it should be said that employing the deicing system (without a heat pump) developed in this study may not keep the slab free from snow consistently during a snowfall. However, this deicing system is still effective if the snow-melting process can be accelerated by using the deicing system because the conventional deicing method was also conducted to accelerate the snow melting.…”

“…The upper limitation of heat flux that could be provided by the deicing system (without a heat pump) in this study is q max = Q max / A heated = 1200/15 = 80 W/m 2 . However, this level of heat flux was much lower than the calculated heat flux, which could keep the slab free from snow ( A r = 1) during snowfall according to previous research . Therefore, it should be said that employing the deicing system (without a heat pump) developed in this study may not keep the slab free from snow consistently during a snowfall.…”

“…There are some applications of bridge deck heating using geothermal energy; however, only two cases use pile heat exchangers . Additionally, numerical methods have been proposed to investigate the performance of bridge deck snow‐melting systems using energy piles …”

“…9,14,15 Additionally, numerical methods have been proposed to investigate the performance of bridge deck snow-melting systems using energy piles. 7,16,17 According to previous studies, there are two main kinds of operation patterns of ground source bridge deck heating systems. The first one is the circulating fluid flow out of the energy pile which when in the bridge deck was heated by the heat pump.…”