| With the social progress and development, people pay more and more attention to the quality of air indoor. Air conditioner becomes a indispensable facility. Especially on different occasions, people have different needs on air handling. Air processing end with the fixed form such as fan coil and fresh air system can no longer meet the need. If we put the processing equipment with different function to assembly together, then the adapt ability is bad. Thus, the concept of combined air condition system is put forward. Combined air condition system can supply air, filtrate, cool, heat, humidity air, purify air and reduce noise. It can take a lot of complicated process of air, with a air volume range from 2000m3/h to 20000m3/h.It can also meet different conditions of use and all kinds of installation requirements. However, it is taking long time and inefficiency to design a complex combined system if only with manual design. In addition, it is hard to have equipment selection optimization. Therefore, it is more efficient to develop a kind of software which can constitute vary of section to a unique unit and select the component of each section. The main content of this paper contain:Firstly, calculation of the physical properties of moist air is studied and two applicable and efficient fitted formulas are presented to calculate the temperature of saturated steam in light of its pressure. Iteration model of the physical properties of moist air is also established. On the basis of continuity equation, energy equation and momentum equation, this paper defined heat transfer model in dry and wet situation.Secondly, lumped parameter model is designed, and a performance analysis of fin-tube heat exchanger under a specific condition is carried on. The influence caused by the variation of structure and situation is analyzed. Based on this model, we analyze and compare the beneficial coefficient with different structures, thus the basis for the structure optimization is provided for fin-tube heat exchanger.Thirdly, based on the application of the fan similarity theory in combined air condition system, formulas of the fan similarity theory is summarized. Data fitting is carried on for the fan characteristic curve, and the result is analyzed. A nested type curve fitting method is able to satisfy the trend of physical model and the precision of mathematical model.Fourthly, the professional and object-oriented design and simulation software for combined air condition system is developed using Visual Basic, based on the previous design and simulation model. The calculation of software, which boasts high applicable values for the designers and consumers of combined air condition system, is relatively accurate, speedy and has a friendly operating interface. |
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