Development of a New Exhaust Air System for Combined Air Compressor and Dryer System

In this work a new exhaust air system for rotary screw compressors with integrated refrigeration dryers has been developed. The new system unites both, the exhaust air flow out of the compressor and out of the refrigeration drier and in such a way the overall exhaust air and hence the overall heat are exhausted through one single air duct. For the development of the system, the ASD 50 T SFC compressor system from KAESER Kompressoren SE [1] was used. Because of the slight overpressure in the exhaust air duct due to the cooling radial fan in the compressor, a jet pump was designed and placed into the main exhaust air duct to reduce the static pressure in the main duct. In such a way, after the jet pump the exhaust air of the refrigeration drier is sucked into the main exhaust air duct through an intake fitting. The nozzle and the intake fitting of the exhaust air duct were first designed by using the commercial CFD solver CFX from ANSYS. The nozzle length, angle and diameter were varied to determine the best geometry. In order to validate the components designed by CFD simulations, three of the designs were manufactured and measured in the compressor laboratory at Coburg University. Therefor heat and velocity measurements in the exhaust air ducts have been done. Also the flow of the exhaust air was visualized using smoke and laser sheets. The simulation and experimental results are shown in detail in this work.