Design of an Air Curtain Device

An air curtain is to be used in the doorway of an industrial building to prevent the penetration of cold air into the building. The task is to dimension this air curtain device for the following climatic conditions  

The wind velocities are local values at the height of the doorway, so no additional wind sheltering coefficients or height corrections are necessary. A solution is sought for which both situations above can be handled with the same air curtain device by just changing the fan speed and the heating power of the air curtain. 

The building (see Fig. 7.95) is 12 m high and has three large openings. The doorway for which the air curtain is designed is on the ground level, has dimensions 4 m (height) x 6 m (width), and is intended primarily for vehicular traffic. 

There are two large openings in the upper part of the building Uqj, which is 4 m wide x 2 m high, and Uq2, which is 2 m wide x 1 m high. The lower-level of 5 m. Otherwise the building envelope is assumed to be airtight. This information is summarized in Table 7.29. 

The unbalanced local exhausts take their makeup air through the building openings  

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