Internet-based Hvac Cad Development

HVAC CAD based on Internet provides active design mode that is different from the traditional HVAC CAD, the data can be shared in more degree and the designing result can be optimized. It provides the base for developing the HVAC CAD with the developing technology of Internet and computer. The paper analyzed developing environment, mechanism, the overall application framework and then presents the key technology in the process of developing the HVAC CAD. It Includes:1. On the base of analyzing the developing process of traditional HVAC CAD and feature of developing language, the author presents the configure of hybrid language for the Internet environment. On the base of the requirement of HVAC CAD's module based on Internet, presents the software's whole framework and the two key technologies, which are data flow and component object model. At the last, analyzes the software's traditional typical developing model and selects the combination model of the object-oriented method and quick prototyping method as developing the whole HVAC CAD model based on network.2. With the research of the topological architecture of LAN, communication mechanism, the organization type of HVAC database and its developing method, presents several realization technology of database based on the Internet. The disadvantage of updating the data not on time can be overcome, because the designer and manufacturer can actively use data resource with the database on the server.3. Analyzing and building the three-tier architecture of network and developing environment, presents the method of component-object-model and develops framework of data flow. In order to improve reusability of hereditary software module, presents the concept and method of reverse software and reengineer.4. The key technology in the designing process of HVAC CAD is making-decision that directly decides the designing result. Aiming at the condition of many variable factor making-decision of the heater/chiller plant, the author puts forward the AHP (analytic hierarchy process) model to explain the method of the making-decision in the Internet environment. The key technology was pointed out that is the dynamic drawing method, and the parameter was cited from the database of the server in the designing process. At last, the key technology was analyzed and the method was pointed out after researching method of data and drawing integrated in HVAC CAD, in order to improve the efficient in the designing process.5. The HVAC CAD's interface based on Internet is media which designer can inputthe data and the module can be initialized. The mechanism that the data transmitted between interface and application was presented in the paper. Due to the difficulty for the helping file updating, the paper presents the method of building the helping file in the Internet environment of the HVAC CAD which included the method of using the module, designing criteria, classifying and saving the documents.The purpose of researching method to develop HVAC CAD based on Internet are applying the its technology to HVAC designing and reducing the repeated labor during the developing software, improving the designing efficiency and designing quality with the Internet's feature which is sharing information and active designing mode.