Effect of opening diffuser and return vent location on air quality, thermal comfort and energy saving in desk displacement ventilation (DDV) system

Document Type : Full Lenght Research Article


1 Semnan University

2 Student of BSC, Semnan University, Semnan, Iran

3 BSC Student, Semnan University, Semnan, Iran


Recently, many investigations have been performed on return vent height; showing that the height of 1.3 m from the floor is the best height for this vent. In this article, the effect of distance between opening diffuser and return vent was investigated on air quality, thermal comfort and energy saving. The results showed, by increasing the distance between opening and return vent up to 5 m, the return vent could be placed near the floor at height of 0.6 m without any unacceptable result in indices. Therefore in this case, energy saving of 15.8% could be achieved rather than 8%, 10.9% and 15.2% in other cases. But, the air quality was lower than other cases. The case which brought better air quality and more thermal comfort with acceptable energy saving of 15.2%, was when the opening and return vent were relocated at maximum distance between them (5 meters) and return vent was placed at the suggested height of 1.3 m from the floor, which was the optimum case in this research.


Main Subjects

Volume 5, Issue 2
October 2018
Pages 139-148
  • Receive Date: 22 October 2017
  • Revise Date: 29 May 2018
  • Accept Date: 21 June 2018
  • First Publish Date: 01 October 2018