Study On Basic Of Application Of Cool Storage Materials For Refrigerated Transport Vehicle

Recently, with the increasing demand for perishable food, the refrigeration industry has become one of the industries with large energy consumption. So it is necessary to increasing energy efficiency and develop new energy. The new mode of transportation which is the combination of cold storage technology and refrigerated transport has become a new issue under discussion and the preparation for cold storage materials with different phase change temperature becomes the key to the new mode. Nowadays there are only few low temperature phase change materials(PCM) with the temperature range from-10℃to-20℃. Therefore, inorganic PCMs with low temperature, high latent heat value, small degree of super-cooling and great cycling stability are investigated and applied in the dynamic simulation research for cold storage plate.This paper presents the research on the PCMs used for refrigerated transportation equipment. PCMs with low temperature and high latent value are developed and tested for the phase change temperature, latent heat of phase change and other thermophysical properties. Performance of the PCMs in the cold storage plate is also studied by dynamic simulation.(1) Different inorganic PCMs are compounded with different ratio. Cold storage medium HSW-9and HCW-5which can be used for refrigerated transportation equipment are prepared by cooling curve method. Nucleating agents and thickeners are added to decrease the degree of super-cooling and prevent the phase separation of the PCMs. The degree of super-cooling of HSW-9and HCW-5after modified decreases61.2%and43.2%respectively and there is not obvious phenomenon of phase separation.(2) The thermo-physical properties including latent heat value and phase change temperature of the modified HSW-9and HCW-5are investigated by differential scanning calorimetry (DSC) method. The latent heat value of multiple inorganic PCM is276kJ/kg for modified HSW-9and257.6kJ/kg for modified HCW-5. The phase change temperature of the PCM is-9.6℃for modified HSW-9and-18.8℃for modified HCW-5. The variation of phase change temperature and latent heat value is small after50times charging and discharging process. The variation ratio of the latent heat value is1.29%for HSW-9and0.31%for modified HCW-5. The variation ratio of phase change temperature is2.06%for modified HSW-9and0.53%for modified HCW-5. Therefore, the modified HSW-9and modified HCW-5have good heat stability and there is no phase separation.(3) Numerical simulation is carried out to study the solidification process of the PCH in the cold storage plate. The phase distribution and temperature distribution are investigated in the plate. The effect of the inlet flow rate and inlet temperature on the outlet temperature and charging capacity is also researched. The result shows that the solidification process of the PCM starts from outside of the cold storage pipes. The PCM solidifies fast at the beginning of the charging process and then slows down gradually. With constant inlet temperature, the convective heat transfer coefficient, the growth rate of the charging capacity and heat transfer temperature difference inside and outside the tube increase with increase of flow rate of the heat transfer fluid, while the average temperature of the heat transfer fluid in the pipe decreases with the increase of the flow rate. With constant inlet flow rate, the heat transfer temperature difference inside and outside the pipes is larger and heat transfer efficiency is higher with the drop of the inlet temperature, moreover, the growth rate of the charging capacity is higher and the complete time is smaller.