Refrigerated Containers Thermal Performance Theory And Experimental Research

With the development of the manufacturing industry and the need of the refrigerated containers in the world market, research on the thermal engineering property experiment system for refrigerated container has more instruction.The research works in this paper focus mainly on the following aspects:The design characteristics, main structures and preliminary operation situation of refrigeration unit control system are described. In every refrigerated container system, a single-chip microprocessor has been used. It has been operated hi laboratory and factory quit well.This paper introduces the formulation, which is used hi analyzing the heat transfer of refrigeration unit. Based on the principle of heat transfer, the unsteady state theory analyzing the heat transfer coefficient of refrigeration unit is established. Using mathematical treatment, the author simplified the equation to apply to the practical measurement and the experimental verification is made. The theory and method of measuring heat transfer coefficient is presented. A new method measuring the toted heat transfer coefficient of refrigeration unit is presented on the base of theoretical analysis and verifying experiments, then the total heat transfer coefficient of refrigeration unit can be calculated out through the experiment data.An automatic measuring and controlling system for refrigerated containers is also presented. The system of automatic detection and temperature and humidity control in refrigerated container laboratory center consists of an IBM-PC computer and two monolithic. The method using a series of transducers that is applied hi the system of automatic temperature detection makes the system more reliable and economic.The qualities of many Supervisory Control And Data Acquisition software are discussed in this paper and the method of using Intouch to develop application software is introduced. Intouch so as to implement the function of A/D and I/O in the software of Intouch are also described. Finally a typical application example, the thermal engineering property experiment system for refrigerated containers is illustrated.Research of thermal engineering performance test facilities for refrigerated containers-the test standards and methods are deeply analyzed. Airtightness test, heat leakage test and performance test (with refrigeration unit) are done on the developed test facilities. The process of the experiment system, used hi measuring the thermal engineering properties of refrigerated containers, is thoroughly discussed. The actual results of control are also given with container-tests carried out on the system. The tests show the system levels the relevant standards set by ATP and ISO, which are proved to be a successful one.Airtightness test shall be carried out when the temperatures inside and outside the refrigerated containers should be stabilized within 3K of each other and should both be within the range 288K to 298K. Air shall be admitted to the container to raise the internal pressure to 250?0Pa and the air supply regulated to maintain this pressure. Once steady test conditions have been established, the airflow required to maintain this pressure shall be recorded. This test shall be carried out after all structural tests have been completed and prior to the heat leakage test. For the said refrigerated containers, the air leakage rate, expressed hi standard atmospheric conditions is 2.38 m3/h, not exceed 10m3/h.IIHeat leakage test shall be carried out to establish the heat leakage for the refrigerated container. The inner heating method only shall be used. Three heating device shall be placed inside the insulated body of the container and thermal equilibrium shall be established between the power of the heating devices and associated fans, and the heat flowing out through the insulation. The electric heating elements shall be operated at temperatures sufficiently low to minimize radiation effects. Air should be circulated over the exterior surfaces of the refrigerated container as a velocity...