Determining the optimal terminal box airflow is a complex process which is influenced by various factors, such as weather condition, supply air temperature, primary air fraction and internal load. A guideline for determination of a cost efficient minimum airflow setpoint for VAV terminal box units is drawn in this research. The most efficient optimal minimum airflow setpoint should not be a fix setting, but should be changing with zone load and ventilation requirement. A fixed minimum airflow is used in conventional control strategies. The terminal box minimum airflow required is not a constant since the supply air temperature, fresh air fraction and zone load are different. It is important to set up the minimum airflow to ensure IAQ and thermal comfort and to minimize energy consumption. Analysis has been carried out to compare how the supply air temperature, fresh air fraction and zone load affect the minimum airflow setting of an exterior zone. And 30% of design airflow is not always a good number, and may cause comfort issue or ventilation problem. If the minimum airflow is set higher than required, terminal boxes will have significantly simultaneous heating and cooling, and consume more fan power in the AHUs. If the minimum airflow is set lower than required, indoor air quality (IAQ) will be a concern. Energy saving ratio study is conducted to estimate the energy saving benefit by implementing an optimized minimum airflow.

This diploma thesis deals with a creation of a “Classification Document” of asynchronous motors with a short-circuit armature with axial heights of 355, 400, 450, 500, and 560 mm. Furthermore, it is concerned with a creation of an integral design documentation for the production and assembly of these motors at the company TES VSETÍN, s.r.o. By writing this diploma thesis I would like to achieve a simplification of communication with the customers during the processing of asynchronous motors orders and to speed up the processing of asynchronous motors orders not only in the design department but also the complete technologic preparation of the production which will surely be provided by this integrated documentation.

The work is focusing on dynamic effects of short-circuit currents, more precisely dynamic effects of short-circuit currents on switchgear cabinet (terminal box). The work was designated to a concrete construction type of two switchgear cabinets located on rotating machines via company Siemens Electric Machines Drásov s.r.o.. The switchgear cabinets are designed for non-explosive environment where the air is used as an insulating medium. The task was to determine how the device will behave during the three-phase short-circuit and three-phase short-circuit with earth/ground connection. The following programs were used for the calculations and simulations: Ansoft Maxwell 16.0, Ansoft Maxwell 2015 and ANSYS Workbench 16.0. By using these programs the effects of forces which acts on current paths in cabinet caused by the passage of short-circuit current were simulated, statically and also dynamically. Further the effects of pressure acting on cabinet frame during the arc short-circuit have been statically and dynamically simulated. All the results are summarized in the conclusion. Conclusion also contains the final evaluation of the functionality of both switchgear cabinets.