Digital Design Platform For Combined Air Conditioning System

With the development of domestic economy, people pay more and more attention to the quality of air indoor. Combined air condition system can filtrate, cool, heat, and humidify air, take a lot of process of air. So it is used more an more frequently. The dimension and construction of Combined air condition system are defined by the load of building and the requirement of owner. So it can not be used in batch manufacture. Therefore, it is necessary to develop a kind of software witch can constitute vary of section to a unique unit and select the component of each section. This software can simulate the performance of fin-tube heat exchanger on different condition, it can be used in optimized selection of fin-tube heat exchanger and fan, then export selection report document and two-dimension engineering drawing.The main content of this paper contain:Firstly, heat exchange and resistance model of the air side and water side are analysed in the aspect of definition region and continuous peculiarity. The A.R.Elmahdy & R.C.Bigg equation,McQuiston equation,Gray&Webb equation and C.C.Wang equation are compared, Gray&Webb j factor model is appled in calculation. According to the value of Re, three different equations of waterside are applied in calculation. This software can distinguish unreasonable input data and determine the dry and wet situation.On the basis of continuity equation, energy equation and momentum equation, this paper defined heat transfer model in dry and wet situation.Secondly, established a lumped model of fin-tube heat exchanger, compared the result of simulation with that of experiment. The influence caused by the variation of structure and situation is analysed. Some designation and selection principles are drew.Thirdly, the application of fan simulation are described in combined air conditioning system fan selection. Three selection methods are put forward. Centrifugal fan database is established, which makes the process of fan peculiarity examination and database updating easier. Fourthly, a software for design and simulation of air handling unit is developed. Basing on mathematical models, which has friendly inferface, fast and convenient calculation speed.