Development and validation of software for designing industrial ventilation systems

Designing of a ventilation system is a complex process. In addition to the time consuming calculations of each branch, it requires iterative calculations for balancing parallel branches. Designing of a proper hood, selecting of appropriate duct diameters and choosing of suitable fan are designing processes in which the error may enforce to decrease the system performance and impose additional costs to the system. Error is likely in manual calculations. In present study, a software tool was developed and validated for local exhaust ventilation system design and calculations. The program was written in Visual Basic. Validation of the software was carried out in two parts. The perfection of the provided codes was studied first. In the second part of the validation process, computational results were studied. For this purpose, the validation was conducted in three steps. The results of each part of the program were compared with the results of manual calculations for simple example, benchmark data, and the results obtained from a credited software program. The Bland-Altman analytical method was applied to statistically compare the overall results. The results revealed that in single hood ventilation systems where the ducts are connected in series, the maximum difference between similar results of the program and benchmark data was 1.27% and the least difference was 0 percent. In complex systems with more than one hood and parallel ducts, the maximum disparity between two similar results gained from this program and either benchmark data or a credited program was 1.77% while the minimum disparity was 0%. Bland-Altman analyses showed that standard deviation of the results from the application of this program to 38-duct pieces was in the range of ± 0.01% for velocity pressure, static pressure as well as total pressure. The present software is a reliable tool for local exhaust ventilation design.