This master thesis is about an investigation of anti-moisture methods for a nonhermeticelectronics enclosure containing a number of printed circuit boards(PCB) and placed in a severe climatic environment. The relevant theoretical background was provided first. It included the impact of moisture on electronics, some useful psychrometrics concepts, heat transfer fundamentals, introduction of environmental test, temperature and humiditysensing techniques, computational fluid dynamics (CFD) modelling, antimoisture methods and commercial heaters in the current marketing. Then a CFD modelling methodology was developed and validated based on experiment data. An extra heater was added to the enclosure to prevent water adsorption on printed circuit assemblies (PCA) surfaces. The heat dissipation and switch-on period strategies were parametrically studied in order to maintain the internal relative humidity below 60% in the vicinity of PCA surfaces, according to the relative humidity control method. In the end, results obtained from the environmental tests and the CFD simulations were presented and analyzed. Conclusions and future work were also discussed.

<p><p>This master thesis is about an investigation of anti-moisture methods for a nonhermeticelectronics enclosure containing a number of printed circuit boards(PCB) and placed in a severe climatic environment.</p><p>The relevant theoretical background was provided first. It included the impact of moisture on electronics, some useful psychrometrics concepts, heat transfer fundamentals, introduction of environmental test, temperature and humiditysensing techniques, computational fluid dynamics (CFD) modelling, antimoisture methods and commercial heaters in the current marketing.</p><p>Then a CFD modelling methodology was developed and validated based on experiment data. An extra heater was added to the enclosure to prevent water adsorption on printed circuit assemblies (PCA) surfaces. The heat dissipation and switch-on period strategies were parametrically studied in order to maintain the internal relative humidity below 60% in the vicinity of PCA surfaces, according to the relative humidity control method.</p><p>In the end, results obtained from the environmental tests and the CFD simulations were presented and analyzed. Conclusions and future work were also discussed.</p></p>

<p>This master thesis is about investigation a power efficient anti-moisture device thatcan be implemented in electronic enclosures in severe climatic environments.First, some of the existing knowledge and previous works were introduced. Then arelevant theoretical background including three main approaches in humiditymanagement are described, comparison between the enclosure heaters and localheaters, some psychrometics concepts that have been used in the project, heattransfer fundamentals, environmental test basics, some humidity and temperaturesensing techniques, computational fluid dynamics, programmable logic controlfundamentals, comparison PLCs with microcontrollers was provided.A series experiments have been performed in order to find the power efficient andmost effective anti-moisture method. Based on the analysis of the experiment data,the local heater system has been designed. CFD assisted parametric study of thelocal heater has been performed in order to find the best feasible design includingthe size and location. The local heater has been built based on the results ofparametric study. Different materials have been tested in laboratory in order tofind the proper material for final prototype of heater. The implemented localheater has been integrated with programmable logic control device. The controlalgorithm has been developed for activation/deactivation of local heater. The logiccontrolled PCB local heater has been experimentally evaluated.In the end the results achieved from environmental test have been presented andanalyzed. Some conclusions on the results and also future work have been discussed.</p>