Experimental Research On The Frosting And Defrosting Characteristics Of Constant Temperature And Humidity System

Refrigeration is the necessary step during storing food, keeping fruit and vegetable fresh, and refrigerating the biology. How to handle the economic application of this step has a huge effect on the whole process. The frosting phenomenon during the refrigeration plays a very important part in the quality of the food and the stability of the refrigeratory. According to this, research on the experiments about the frosting and defrosting of the constant temperature and humidity system has been made.Through the control system based on the PLC, the thesis has studied the evaporation temperature, the wing temperature and the difference of the pressure, which based on different storing temperature, different humidity and the blowing velocity. The experiments'results show that differences of the frosting quantity are obvious on the surface of the evaporator during different experiment conditions. With the fall of the storing temperature, the rising of the humidity, and the fall of the blowing velocity, the frosting quantity will rise in certain range.The conditions that frost easily have obtained through the experiments, which become the basis of the defrosting experiments. During the defrosting processes, many methods have been used to contrast, such as stopping the refrigerating and the non-stopping the refrigerating defrosting, and defrosting at different time. Finally, the right way of defrosting was obtained through analyzing the experiments'results.