Mathematical Model And Software Development For Simulation Of Multi-Type Refrigerators

Refrigerators are commonly used as one of the household appliances. People from different countries and regions have different requirements about refrigerators due to the varying living habit. In order to meet the requirements of different customers, the refrigerator manufacturers usually design and develop series products of refrigerators which are applied to the customers from all over the world. Compared to the traditional prototype-testing design method, the simulation design method can shorten the design cycle, cut the cost and decrease the amount of prototype. Nowadays, the simulation method is more widely used by the refrigerator corporation. Therefore, it is necessary for the corporation to develop simulation platform to simulate different types of refrigerators.This paper proposes the development concept of the integrated simulation platform, and then put forward the implementation method of the core module of the software, and finally put forward the implementation method of the software interface. All the research work is based on the existing research of the refrigerator technology, knowledge of refrigeration model and software. The main works is reviews as follows:1- Summarize the character of the commonly used refrigerators and make classification of the refrigerator type according to the requirements of model establishment. Then put forward the framework and implemental method of the multi-type refrigerators simulation platform.2- Put forward the establishment method of the core module of the multi-type refrigerator platform, the main achievement is as follows:1) The method of data memory and transfer for multi-type refrigerators. There is a one-to-one relationship between refrigeration type and data structure when the traditional data-saving method is used. However, this method will lead to data redundancies and data coupling, and affect the software robustness. This paper introduces the object-oriented method to realize the data memory and transfer for multi-type refrigerators. The data and operation of the data are encapsulated together, and thus increase the robustness and extension of software.2) The method of system control for multi-type refrigerators. There is a one-to-one relationship between refrigeration type and the system control algorithm when the traditional data-saving method is used. In the system of multi-type refrigerators, since different refrigerator system use different system control algorithm, and control algorithm further involves the calling of different components, the traditional way will increase the system complexity. This paper proposes the integration method of system control algorithm, which is based on the judgment of the running cycle of next time step. That is to say, to decide the cabinets to be cooled. This method solves the coupling problem of the system and components.3) The method of computation model. For multi-type refrigerators, different types of components are used, the simple model can't be used due to the variety of the working principle, and the use of different models for each combination type of components will greatly increase the complexity of the software as well. This paper establishes the universal model for compressor, heat exchange and cabinet. For compressor universal model, the method to compute compressor power and mass flow rate under any frequency is established to realize the simulation for both on-off compressor and variable-capacity compressor; For heat-exchanger universal model, the method to decouple the heat-exchanger connecting ways and system running state is established to realize the simulation for all types of heat-exchanger; For cabinet universal model, the universal method to describe cabinet layout type and inside wall type is established to realize the simulation for different types of cabinet.4) The output module. The precision of energy consumption results is affected by the initial moment of steady state. The traditional software used experience data as the initial moment. Since the initial moment of steady state is related to refrigerator running cycle and thermal capacity of cabinet, the traditional method is no longer appropriate for the system of multi-type refrigerators. In this paper, the universal method is put forward to calculate the initial moment of the steady state.3- For the convenience of the users, the implemental method of the software interface is put forward, which includes the implemental method of the interface for multi-type compressor, heat-exchanger, and cabinet. Also, the design method of the operation structure is established. 4- The comparison between predicted results and test data indicates a good predicting precision of the system performance for multi-type refrigerators.