Study On Dynamic Air Infiltration And Dynamic Cooling Process Of Refrigerated Transport Unit

Nowadays refrigerated transport energy consumption has become a major focus of the era of energy shortage, with a rapid development of cold chain logistics industry today. Heat leakage through the Refrigerated compartment and the energy consumption of the refrigeration unit are major causes of high cost in the refrigerated transport. Incorrect operation and administration also increases the energy consumption of refrigerated transport. Air infiltration, as one of the influencing factors of heat leakage through the refrigerated compartment body, have a close relation to the air tightness and the movement of the compartment. On the basis of analyzing development and the energy consumption status of refrigerated vehicles in China, the theory of the Dynamic air infiltration and the cooling process in refrigerated container used for road transportation is researched and the experiment analysis is made in this paper, with a experiment platform of refrigerated transport unit.The main research contents are as follows:(1) Through literature search and reading, this paper analyzes results of energy consumption in refrigerated transport domestic and overseas, and summarizes the new development trend. Based on the development of refrigerated transport, the development tend of refrigerated vehicles in China is prospected。Also, the necessity of researching on the dynamic energy consumption status in refrigerated vehicles.(2) Existing vehicle air tightness indicators are analyzed and different computational methods of air infiltration are compared. After the analysis of the characteristics of the refrigerated vehicles, an equation from the aperture method is defined for researching on its dynamic air infiltration, which is L=(1+k)n·Aw·(Cn·Cf△P+△Pb)b. By using tracer gas method, the value or dynamic air infiltration is measured and then the parameters in the equation are determined, including the wind pressure coefficient and thermal pressure coefficient. The experiments improved the using of research achievement on the aperture method, and proved the feasibility of the method.(3) According to the regularity of dynamic air infiltration in refrigerated transport unit, influencing factors, such as external environmental condition and heat conduction through the Compartments body, are comprehensively considered, and a mathematical model is finally built for the cooling process in the refrigerated container, the validity of which is proved in the experiment text. Then an analysis is made for the affects form the velocity, the air infiltration value, the difference between the inner and outside, the refrigerating capacity of the set etc on the cooling performance in the refrigerated compartment. The results of calculation and test comparison show that while the velocity value is60km/h, the temperature in the test compartment get down most rapidly. The suggestion is raised that the cooling speed rate should be a reference frame while choosing the refrigerated set and measuring the dynamic air infiltration of the compartment.The above content is trying to do a tentative exploration on the dynamic air infiltration of refrigerated vehicles, and do a research on the cooling velocity in the compartment for the function of ensuring the food safety. All of these could supply a reference for the study on the dynamic energy consumption and the researching method.