Micro-environmental control for efficient local cooling: Results from manikin and human participant tests. (August 2019)

• Record Type: Journal Article
• Authors: Kong, Meng; Zhang, Jianshun; Dang, Thong Q.; Hedge, Alan; Teng, Teng; Carter, Brian; Chianese, Chetna; Ezzat Khalifa, H.
• Is Part Of: Building and environment. Volume 160(2019)
• Publication Date: 2019-08
• Subjects: Micro-environment -- Thermal comfort -- Manikin test -- Human participant test -- Local cooling; Buildings -- Environmental engineering -- Periodicals; Building -- Research -- Periodicals; Constructions -- Technique de l'environnement -- Périodiques; Electronic journals; 696
• DOI: 10.1016/j.buildenv.2019.106198
• Languages: English
• ISSNs: 0360-1323

Abstract

Abstract: The micro-environment in this study refers to the air space and environment around a person that directly impacts their thermal sensation. This study aims at evaluating the performance of a newly developed micro-environmental control system (μX) designed to cool the occupants locally for thermal comfort when the temperature in the ambient unoccupied space is raised from 23.9 °C to 26.1 °C in summer to reduce the HVAC cooling load. The μX was tested first with a 20-segment thermal manikin wearing summer clothing in a full-scale stainless-steel chamber and then with human participants in a climate chamber. Results show that the heat loss by the manikin increased with the distance between the μX air supply diffuser and the manikin and decreased with the clothing insulation. Changing the air delivery angle from 0° to 10° from the horizontal direction resulted in additional heat loss from the manikin. The heat loss from the manikin was found to be positively correlated with the supply air flow rate, but negatively correlated with the supply air temperature. However, the overall cooling efficiency dramatically increased with the supply air temperature. Overall, both the manikin test and the human participant test showed that the μX was able to cool the occupant in a room of expanded temperature set-point, and the Clothing Independent Thermal Comfort Model gave a consistent prediction with the human participant test. However, slight thermal discomfort was reported when the μX was used due to the effect of clothing, season, metabolic rate and local draught. Highlights: The heat removed by the jet is sensitive to the distance between from the manikin and clothing material. The cooling efficiency increased with the supply air temperature. The Clothing Independent Thermal Comfort Model was able to give a good prediction of the thermal sensation with and without the μX. The human participant test results showed the μX could cool the occupants but did not improve the thermal comfort perception.