Study On Thermal And Cooling Equipment Of Oil Industry Based On Phase-Change Materials

This paper based on "twelfth five-year" national science and technology support plan "heat and cooling equipment research and development and application demonstration",according to characteristics of high temperature working environment to the oil industry,on the basis of phase change materials to design a set of heat and cooling equipment,can make the workers working in high temperature environment for a long time to maintain thermal comfort condition,to improve the safety of workers working in a high temperature environment is of great significance.On the basis of the engineering thermodynamics has established the human-clothing-environment system heat transfer model of human body thermal model is established,garment surface heat transfer model and phase change heat transfer model.Human body heat dissipation model shows that the main factors influencing the human body heat to the human body skin sweat evaporation rate,garment surface heat transfer model shows that the main factors influencing the effect of clothing heat moisture transmission for clothing material permeability,phase change heat transfer model shows that the main factors influencing the effect of phase change materials thermal control for the phase transition enthalpy and thermal conductivity.According to the project actual demand to choose is tetradecane and dodecanoic phase change materials for cool suit,both distribution is obtained by material distribution formula after the phase transition temperature of the curve,determine the ratio of positive tetradecane and dodecanoic 9:1.Differential scanning calorimetry and thermal conductivity experiments showed that the phase change temperature and enthalpy of the composite materials met the requirements,and the thermodynamic properties of the materials were stable after 300 cycles of cooling.Polyethylene was used as the coating material to encapsulate the phase-change material and place it on the chest and back of the body where the maximum heat dissipation was found.The fan was selected as the auxiliary equipment to increase the evaporation rate of sweat on the skin surface.Based on 20 workers in four kinds of skin temperature of the environment and the subjective questionnaire on the basis of thermal sensation,Markov distance criterion established by subjective feeling and average combination of skin temperature,the thermal comfort evaluation index system.The system shows that when the temperature of the human body skin in [33.57,34.50)this interval can determine when the human body in a state of thermal comfort.The warm false body at 37 ?,50% humidity environment in cool suit 5.5 hours of simulation experiment,the experimental results show that the cool suit within 5.5 hours can maintain dummy mean skin temperature does not exceed 34.20 ?,cool suit can keep the body in the above environment in a state of thermal comfort.