Thermal performances of porous snow by a hydronic heating system at different weather conditions
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Thermal performances of porous snow by a hydronic heating system at different weather conditions Wenke Zhao1 · Lei Li1 · Wei Wang1 · Yaning Zhang1 · Wentao Su2 · Xin Chen1 · Bingxi Li1 Received: 15 December 2019 / Accepted: 9 February 2020 © Akadémiai Kiadó, Budapest, Hungary 2020
Abstract The snow on the road in the cold regions is easy to cause slippery conditions, which are dangerous for vehicles and people. To remove the slippery conditions, the hydronic snow melting system has been applied to remove the snow on the road. This study proposed a transient finite volume model with snow porous characteristics, to analyze the snow melting performances by a hydronic heating system. Three primary environmental parameters (snow thickness, wind velocity, and air temperature) were selected to compare the average road surface temperature and snow melting ratio. Then, the snow melting performances using a hydronic road heating system were analyzed. The results showed that the snow melting ratio was rapidly dropped as the snow thickness was increased from 10 to 90 mm. The snow thickness had a slight influence on the average road surface temperature in the melting process, whereas it had a significant impact after the snow was completely cleared. When the wind velocity was increased to 5 m s−1, the critical melting ratio appeared at around 0.7. The wind velocity had a significant influence on average road surface temperature when the average road surface temperature increased more than 273.15 K. There is a critical air temperature existed between 263.15 and 258.15 K, which limits the snow melting process at current supplied fluid temperature (313.15 K), indicating that more energy was need to supply to overcome cold weather. This study offers a good reference for the design of a hydronic snow melting system in severely cold regions. Keywords Hydronic snow melting system · Road unit · Snow thickness · Wind velocity · Air temperature List of symbols Cp Specific heat at constant pressure (kJ kg−1 K−1) Cpa Specific heat at constant pressure of the air (kJ kg−1 K−1) Cpi Specific heat at constant pressure of the ice (kJ kg−1 K−1) Cps Specific heat at constant pressure of the snow (kJ kg−1 K−1) Cpw Specific heat at constant pressure of the water (kJ kg−1 K−1) hc Convective heat transfer coefficient (W m−2 K−1)
Wenke Zhao and Lei Li have contributed equally to this work. * Yaning Zhang [email protected] * Bingxi Li [email protected] 1
School of Energy Science and Engineering, Harbin Institute of Technology, Harbin 150001, China
College of Petroleum Engineering, Liaoning Shihua University, Fushun 113001, China
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H Total enthalpy (kJ kg−1) Hl Total enthalpy of the liquidus temperatures (kJ kg−1) Hs Total enthalpy of the solidus temperatures (kJ kg−1) Mf Ratio of snow melting for the total snow layer Mi Mass of the ice (kg) Ms Mass of the snow (kg) Mw Mass of the water (kg) q Heat flux by conduction (W m−2) qc Convective heat flux above the snow surface (W m−2) qr Heat flux for radiation of long wavelength
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