Experimental studies on the air distribution with ceiling linear diffusers in a room

Guangyu Cao, Mika Ruponen, Kim Hagström, Jarek Kurnitski

Research output: Chapter in Book/Report/Conference proceedingConference article in proceedingsScientificpeer-review


Nowadays, the application of the ceiling linear diffuser becomes very popular in office rooms due to the advantages of the silent operation and the efficient arrangement for the open plan office. However, one of the problems for the producer of the air diffuser and designer of the ventilation and air conditioning system is to determine and specify correctly the throw-length data in order to achieve optimal air movement in the occupied zone. Here, the comprehensive experimental studies were conducted to identify the variation characteristics of the jet throw-length using the ceiling linear diffuser. Totally fourteen cases including seven aspect ratios were measured under the isothermal conditions in a climate chamber with the dimensional size of 10 m *6 m *3.7 m equipped with the automatic measurement system. The results show that the critical aspect ratio regarding to 2D and 3D jet flow differs from the default value, 40, used to predict the jet throw-length by the present design guidebook. The results also confirmed that the jet maximum velocity decay coefficient depends on the details of the diffuser and thus should be identified for each kind of products. The presented methodology suggests a standard process to determine the maximum jet velocity decay coefficient.
Original languageEnglish
Title of host publicationCLIMA 2010
Subtitle of host publication10th REHVA World Congress: Sustainable Energy Use in Buildings
Publication statusPublished - 2010
MoE publication typeA4 Article in a conference publication
Event10th REHVA World Congress: Sustainable Energy Use in Buildings, CLIMA 2010 - Antalaya, Turkey
Duration: 9 May 201012 May 2010
Conference number: 10


Conference10th REHVA World Congress
Abbreviated titleCLIMA 2010


  • Ceiling linear diffuser
  • attached plane jet
  • throw-length
  • maximum velocity decay
  • measurement


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