Uniformity of stratum-ventilated thermal environment and thermal sensation

Cheng, Yong; Fong, Ming Lun Alan; Yao, Ting; Fong, K.F.

doi:10.1111/ina.12097

Cited by 51 publications

(44 citation statements)

References 13 publications

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“…For the supply airflow rates of 7 ACH, 10 ACH and 15 ACH, the average thermal sensation was 0.07, 0.13, and −0.08, respectively. This indicated that the subjects felt neutral at the room temperature of 27 °C, which is in agreement with the findings of our previous studies (Cheng et al., ; Fong et al., ).…”

Section: Results and Discussion: Subjective Thermal Comfort Surveysupporting

confidence: 93%

Experimental investigation into the interaction between the human body and room airflow and its effect on thermal comfort under stratum ventilation

Cheng

Lin

2015

Indoor Air

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Room occupants' comfort and health are affected by the airflow. Nevertheless, they themselves also play an important role in indoor air distribution. This study investigated the interaction between the human body and room airflow under stratum ventilation. Simplified thermal manikin was employed to effectively resemble the human body as a flow obstacle and/or free convective heat source. Unheated and heated manikins were designed to fully evaluate the impact of the manikin at various airflow rates. Additionally, subjective human tests were conducted to evaluate thermal comfort for the occupants in two rows. The findings show that the manikin formed a local blockage effect, but the supply airflow could flow over it. With the body heat from the manikin, the air jet penetrated farther compared with that for the unheated manikin. The temperature downstream of the manikin was also higher because of the convective effect. Elevating the supply airflow rate from 7 to 15 air changes per hour varied the downstream airflow pattern dramatically, from an uprising flow induced by body heat to a jet-dominated flow. Subjective assessments indicated that stratum ventilation provided thermal comfort for the occupants in both rows. Therefore, stratum ventilation could be applied in rooms with occupants in multiple rows.

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Section: Results and Discussion: Subjective Thermal Comfort Surveysupporting

confidence: 93%

Experimental investigation into the interaction between the human body and room airflow and its effect on thermal comfort under stratum ventilation

Cheng

Lin

2015

Indoor Air

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“…Subjective surveys of stratum ventilation also confirmed the deficiency of the conventional control method [27,28]. Even with proper control, the percentage of occupants feeling thermal comfort was generally from 80% to 90%, leaving the remaining occupants suffering from thermal discomfort [27,28].…”

Section: Introductionmentioning

confidence: 81%

“…The widely used thermal comfort model, PMV-PPD, echoes the deficiency of the M A N U S C R I P T A C C E P T E D ACCEPTED MANUSCRIPT 4 conventional control method that even under the optimal condition, at least 5% occupants would feel dissatisfied with the thermal environment [26]. Subjective surveys of stratum ventilation also confirmed the deficiency of the conventional control method [27,28]. Even with proper control, the percentage of occupants feeling thermal comfort was generally from 80% to 90%, leaving the remaining occupants suffering from thermal discomfort [27,28].…”

Section: Introductionmentioning

confidence: 99%

Subzone control method of stratum ventilation for thermal comfort improvement

Zhang

Cheng

Oladokun

2019

Building and Environment

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S u b z o n e c o n t r ol m e t h o d of s t r a t u m v e n til a tio n fo r t h e r m al c o mfo r t i m p r ov e m e n t Z h a n g , S, C h e n g, Y, Ol a d o k u n, M O a n d Lin, Z h t t p:// dx. d oi.o r g/ 1 0. 1 0 1 6/j.b uild e nv.2 0 1 8. 1 1. 0 4 1 Ti t l e S u b z o n e c o n t r ol m e t h o d of s t r a t u m v e n til a tio n fo r t h e r m al c o mfo r t i m p r ov e m e n t A u t h o r s Z h a n g, S, C h e n g , Y, Ol a d o k u n, M O a n d Lin, Z Typ e Articl e U RL This ve r sio n is a v ail a bl e a t : h t t p:// u sir.s alfo r d. a c. u k/id/ e p ri n t/ 5 3 1 0 1/ P u b l i s h e d D a t e 2 0 1 9 U SIR is a di git al c oll e c tio n of t h e r e s e a r c h o u t p u t of t h e U niv e r si ty of S alfo r d. W h e r e c o py ri g h t p e r mi t s, full t e x t m a t e ri al h el d in t h e r e p o si to ry is m a d e fr e ely a v ail a bl e o nli n e a n d c a n b e r e a d , d o w nlo a d e d a n d c o pi e d fo r n o nc o m m e r ci al p riv a t e s t u dy o r r e s e a r c h p u r p o s e s . Pl e a s e c h e c k t h e m a n u s c ri p t fo r a n y fu r t h e r c o py ri g h t r e s t ri c tio n s. Fo r m o r e info r m a tio n, in cl u di n g o u r p olicy a n d s u b mi s sio n p r o c e d u r e , pl e a s e c o n t a c t t h e R e p o si to ry Te a m a t: u si r@ s alfo r d. a c. u k . AbstractThe conventional control method of a collective ventilation (e.g., stratum ventilation) controls the averaged thermal environment in the occupied zone to satisfy the averaged thermal preference of a group of occupants. However, the averaged thermal environment in the occupied zone is not the same as the microclimates of the occupants, because the thermal environment in the occupied zone is not absolutely uniform. Moreover, the averaged thermal preference of the occupants could deviate from the individual thermal preferences, because the occupants could have different individual thermal preferences. This study proposes a subzone control method for stratum ventilation to improve thermal comfort. The proposed method divides the occupied zone into subzones, and controls the microclimates of the subzones to satisfy the thermal preferences of the respective subzones. Experiments in a stratum-ventilated classroom are conducted to model and validate the Predicted Mean Votes (PMVs) of the subzones, with a mean absolute error between 0.05 scale and 0.14 scale. Using the PMV models, the supply air parameters are optimized to minimize the deviation between the PMVs of the subzones and the respective thermal preferences. Case studies show that the proposed method can fulfill the thermal

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“…In other words, a neutral OTS ensured satisfactory OTC. It may be attributed to the thermal uniformity in the occupied zone under stratum ventilation [30]. Fig.…”

Section: Thermal Sensation and Comfortmentioning

confidence: 95%

“…Perforation diffusers and double deflection grilles were used as the supply and return terminals respectively because they had exhibited good performance in a previous study [30]. Three room temperature settings (24 C, 27 C and 29 C) were applied in this series while the supply airflow rate was kept constant at 10 ACH.…”

Section: Experimental Designmentioning

confidence: 99%