Project Description:

The proposed project herein will implement a micro-radiant heating system (MRHS) as a retrofit layer on the surface of existing concrete pavement. The technology will utilize a combination solar photovoltaic/thermal (PV/T) system and novel thermally active materials to keep surfaces free of snow and ice. The self-contained system will effectively provide heating, improve safety, reduce winter maintenance, and eliminating the usage of deicing salt for the control of ice/snow during cold seasons. To enhance the performance, the system will incorporate low operating temperature phase change material (PCMs) based heat transfer fluid (HTF) and surface composition to circulate/store the energy in the system. The latent heat release from the PCMs provide backup source of energy during days when little-to-no-sun is available. As an additional benefit, the system will reduce the number of freeze-thaw cycles experienced by the pavement, improving long-term durability.

Outputs:

A multipronged solution will be performed in this study, as follows:

1. Material Thermophysical Property Analysis
   

   The thermophysical properties of the select low-cost PCMs will be examined prior to thermal investigation of the system. PCMs for this analysis include paraffin oil, blended coconut oil with soybean oil, n-tetradecane and water, and sodium tartrate. Three main types of thermal analysis devices (available in PIs’ research labs) will be used: the Thermogravimetric Analyzer (TGA), the Differential Scanning Calorimeter (DSC), and the Trident thermal conductivity measurement instrument. The TGA first provides information regarding the thermal stability and degradation temperature of mixture over a specific temperature range. This is a vital step as degradation of the PCM in the system will damage the system’s equipment over time. Once verified that the selected PCMs are stable over the specified temperature range, the materials will be tested on the DSC to determine several vital thermophysical properties such as the melting/solidification onset temperatures, specific heat capacity, and latent heat of fusion of the selected mixture. Moreover, the thermal conductivity properties of the selected mixture with respect to temperature can be determined using the Trident thermal conductivity measurement instrument. The PI has extensive background in development of novel PCMs for increased thermal storage capabilities.

2. Small Scale Experimental Setup
   

   Once PCMs’ behavior is evaluated, a small experimental setup will be constructed for the purpose of feasibility analysis and tested. The setup will include a 24 ft2 concrete block, integrated with fluid circulation piping and connected to the available data collection system at the PIs’ roofdeck. The system will be tested quarterly in different weather conditions. The available weather station at the roofdeck provides the precise weather condition of the field on the selected dates of the experiments. The achieved results will be the baseline for further modification of system’s configuration/optimization as well as material’s selection before entering the full-scale analysis.

3. Full Scale System Design and Analysis
   

   The final step of this project is conducting the feasibility analysis of the achieved results in steps 1 and 2 on a full-scale system (depicted in Figure 1) in any existing public transport stations. Figure 1 below shows the schematic diagram of the proposed system configuration. An array of commercially available full-scale PV/T solar collectors will be placed on the roof of the public transport station. A header tank with a closed-loop piping system will also located on the roof of the public transport station to store the heated anti-icing fluid, where the hot PCM outlet effectively provides heat to the concrete pavement and the cooled PCM will be circulated back to the header tank. The excess energy from the PV panels will be stored in a battery pack, providing the electricity for running the pump within the system, therefore, maintain a self-sustaining operation.

_{Figure 1: Schematic of the proposed system: 1) Arrays of PV/T System, 2) Header tank with a closed loop system and 3) RHS loop.}

Outcomes/Impacts:

It is expected to obtain the optimized smart solar ice control system proposed in this study for the application in urban transportation systems for enhancing sustainability and resiliency. The self-contained system will effectively provide heating, improve safety, reduce winter maintenance and eliminating the usage of deicing salt for the control of ice/snow during cold seasons. As an additional benefit, the system will reduce the number of freeze-thaw cycles experienced by the pavement, improving long-term durability.