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Numerical study on thermal indoor environment of an office with hybrid system of chilled ceiling panel and displacement ventilation.

Author(s) : ZHAO L., FENG Y., YUAN F., et al.

Summary

Hybrid air-conditioning systems of chilled ceiling panel (CP) and displacement ventilation (DV) are expected to be more comfortable and superior energy-saving systems than conventional systems. It is very important to determine the optimal indoor design parameters and combined cooling parameters to achieve the most comfortable indoor environment and to save energy simultaneously at the design stage. To this end, CFD simulations were conducted on an office with a hybrid system of chilled ceiling panel and displacement ventilation. Firstly, the impact of the location of heat sources and air diffusers on indoor thermal environment were investigated, keeping the cooling parameters constant. Then, the influence of such cooling parameters as supply air flow rate or temperature of DV, the surface temperature or the area ratio of CP to the ceiling on indoor air temperature and velocity distribution were studied individually. It shows that the lower the air supply flow rate, the stronger buoyant force plays on the room air movement, and the less the convection fraction from the chilled panel to the room air. Higher supply air temperature of the DV creates lower vertical temperature gradient in the occupied zone. Ventilation efficiency also improves as it rises, while the cooling capacity of CP decreases by somewhat. It was found that temperature gradient in the occupied zone becomes less and ventilation efficiency drops as the surface temperature of the CP drops. Changing the area ratio of CP mainly affects the room air temperature above the heat sources. Larger chilled ceiling panel may cause the temperature of the upper part of the room to drop more significantly. And then, the combined effects of lowering supply air temperature and increasing supply air flow rate on indoor thermal environment was also explored.

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Pages: pp. 600-605

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Details

  • Original title: Numerical study on thermal indoor environment of an office with hybrid system of chilled ceiling panel and displacement ventilation.
  • Record ID : 2010-0909
  • Languages: English
  • Source: ACRA-2009. The proceedings of the 4th Asian conference on refrigeration and air conditioning: May 20-22, 2009, Taipei, R.O.C.
  • Publication date: 2009/05/20

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