The purpose of this report is to improve the temperature uniformity, by designing a ventilation system, to improve the flow distribution in a ULUF 500 freezer from Arctiko. The ventilation system will consist of an axial fan and a manifold resembling a perforated plate with 150 holes. These holes are placed in 15 rows with 10 holes in each row along the plate. The report is purely theoretical. Therefore, a Matlab model is created to calculate the flow distribution, using pipe system analysis. This report also contains an analysis of the loss coefficients in the manifold. Finally, the price for the construction and implementation of the ventilation system is examined, to determine if the system is too expensive or will be a suitable option for recirculating the air.