| A | Whole-body surface area (m2) |
| AC | Air-conditioning |
| ADPI | Air diffusion performance index |
| AP | Air movement preference |
| CFIAC | Ceiling-fan-integrated air-conditioning |
| CP | Corrective power (°C) |
| D | Fan diameter (m) |
| EHT | Equivalent homogenous temperature (°C) |
| Iclo | Clothing insulation (clo) |
| HVAC | Heating, ventilation and air-conditioning |
| MET | Metabolic rate (met) |
| NV | Natural ventilation |
| PD | Predicted dissatisfaction due to draft |
| PPD | Predicted percent dissatisfied |
| PMV | Predicted mean vote |
| Q | Heat loss (W) |
| R2 | Correlation coefficient (r) squared |
| RH | Relative humidity (%) |
| SD | Standard deviation |
| SET | Standard effective temperature (°C) |
| Tair | Air temperature (°C) |
| TAV | Thermal acceptance vote |
| TP | Thermal preference |
| Tr | Radiant temperature (°C) |
| TSV | Thermal sensation vote |
| VAV | Variable air volume |
Figure 1
Configuration of the ceiling-fan-integrated air-conditioning (CFIAC) system and climate chamber: (a) three-dimensional layout of the chamber room; (b) vertical section; (c) horizontal section; and (d) set-up for the human subject test.
Table 1
Summary of the thermal manikin tests.
| CFIAC SET-UP | P1 | P1’ | P2 | P4 | |
|---|---|---|---|---|---|
| High-side wall diffuser | Fan off | √ | √ | √ | |
| Medium up | √ | √ | √ | ||
| Low down | √ | √ | √ | ||
| Medium down | √ | √ | √ | ||
| Supply air from an overhead diffuser with no ceiling fan with a room temperature of 26°C | √ | √ | √ | √ | |
| Room temperatures | 23, 26, and 28°C | ||||
| Manikin skin temperature | 34°C | ||||
[i] Note: A few test locations were skipped because they were repeated under specific conditions. For example, for low and medium downward fan directions, location P1 was not tested because it is similar to P2 and P4.
CFIAC = ceiling-fan-integrated air-conditioning.
Table 2
Test conditions for the human-subject experiments.
| AMBIENT TEMPERATURES | 23°C | 26°C | 28°C | ||||||
|---|---|---|---|---|---|---|---|---|---|
| SET-UPS | P1 | P2 | P1 | P1’ | P2 | P1 | P1’ | P2 | |
| High-side-wall vent | No fan | √ | √ | × | × | × | × | ||
| Fan type 1, medium speed, upward | √ | √ | • | • | |||||
| Fan type 1, low speed, downward | • | • | • | • | |||||
| Fan type 1, medium speed, downward | • | • | |||||||
| Fan type 2, high speed, upward | ∞ (comparing with P3) | ∞ (comparing with P3) | |||||||
| Overhead diffuser | ☼ | ☼ | ☼ | ||||||
[i] Note: √ = No fan case and fan type 1 in cool condition; × = no-fan condition; • = with fan conditions at 26 and 28°C; ∞ = fan type 2 upward-operating at a high-speed level; ☼ = comfort evaluations of an overhead flush-mounted ceiling diffuser under an neutral ambient temperature of 26°C. Fan type 1 (Haiku 60, Big Ass Fans, Inc.) has a diameter of 1.52 m and its maximum airflow under downward operation is 4.07 m3/s. Fan type 2 has a diameter of 1.32 m and a maximum airflow under downward operation of 3.17 m3/s.
Figure 2
Test protocol example.
Figure 3
Whole-body corrective power (CP) in Equivalent homogenous temperature (EHT) at different test locations.
Note: The reference case is the ‘overhead diffuser with 26°C room temperature’ condition. Error bars represent the standard error among the three temperature conditions.
Figure 4
Corrective power (CP) in equivalent homogenous temperature (EHT) at local body parts.
Note: The baseline case is the ‘fan off’ condition at each location. + = Warmer than the baseline case; and ‘–’ = cooler than the baseline case. Highlighted values are the top three affected body parts.
Table 3
Statistical results of the human subject test.
| TEST CONDITIONS | WHOLE-BODY THERMAL SENSATION (TSV) | WHOLE-BODY THERMAL ACCEPTANCE (TAV) | THERMAL PREFERENCE | AIRSPEED PREFERENCE | ||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| LOCATION | TEMPERATURE (°C) | FAN OPERATION | AIR SPEED (m/s) | NUMBER OF SUBJECTS | MEAN | SD | MEAN | SD | ACCEPTANCE RATE (%) | COOLER | NO CHANGE | WARMER | LESS | NO CHANGE | MORE | |
| Fan type 1 | Supply air dumping zone (P1) | 23 | Fan off but AC on | 0.32 | 20 | –1.00 | 0.82 | 1.21 | 2.03 | 73.7% | 2 | 9 | 9 | 6 | 12 | 2 |
| Medium up | 0.24 | 20 | –0.02 | 0.73 | 2.25 | 1.40 | 85.5% | 3 | 10 | 7 | 3 | 15 | 2 | |||
| 26 | Fan off but AC on | 0.33 | 20 | 0.13 | 0.69 | 1.96 | 1.42 | 84.2% | 3 | 15 | 2 | 3 | 14 | 3 | ||
| 28 | Fan off but AC on | 0.34 | 20 | 0.28 | 0.50 | 2.13 | 1.37 | 94.4% | 7 | 13 | 0 | 2 | 12 | 6 | ||
| Medium up | 0.22 | 20 | 0.93 | 0.74 | 1.98 | 1.38 | 85.5% | 10 | 10 | 0 | 0 | 10 | 10 | |||
| Fan-jet zone (P1’) | 26 | Low down | 0.73 | 20 | –0.25 | 0.81 | 2.03 | 1.51 | 89.5% | 2 | 10 | 8 | 7 | 10 | 3 | |
| 28 | Low down | 0.72 | 20 | 0.05 | 0.67 | 2.50 | 1.12 | 100.0% | 5 | 11 | 4 | 5 | 10 | 5 | ||
| Medium down | 1.05 | 20 | –0.33 | 1.25 | 2.32 | 1.34 | 94.7% | 4 | 12 | 4 | 9 | 8 | 3 | |||
| Outside the fan zone (P2 or P4) | 23 | Fan off but AC on | 0.03 | 20 | –0.32 | 0.57 | 2.03 | 1.51 | 89.5% | 2 | 11 | 7 | 0 | 13 | 7 | |
| Medium up | 0.34 | 20 | –0.58 | 0.81 | 1.88 | 1.76 | 89.5% | 0 | 11 | 9 | 2 | 16 | 2 | |||
| 26 | Fan off but AC on | 0.04 | 20 | 0.56 | 0.68 | 2.16 | 1.40 | 85.9% | 8 | 10 | 2 | 0 | 8 | 12 | ||
| Low down | 0.36 | 20 | 0.38 | 0.85 | 2.22 | 1.46 | 94.7% | 6 | 13 | 1 | 1 | 13 | 6 | |||
| 28 | Fan off but AC on | 0.03 | 20 | 1.04 | 0.65 | 0.94 | 1.57 | 77.8% | 12 | 8 | 0 | 0 | 8 | 12 | ||
| Low down | 0.36 | 20 | 0.78 | 0.91 | 1.22 | 1.56 | 94.1% | 7 | 11 | 2 | 0 | 11 | 9 | |||
| Medium down | 0.54 | 20 | 0.34 | 0.77 | 2.28 | 1.43 | 100.0% | 6 | 11 | 3 | 3 | 11 | 6 | |||
| Medium up | 0.32 | 21 | 0.78 | 0.91 | 2.13 | 1.43 | 84.4% | 10 | 11 | 0 | 0 | 12 | 9 | |||
| Fan type 2 | Supply air dumping zone (P1) | 26 | High speed up | 0.25 | 20 | 0.18 | 1.00 | 2.61 | 1.48 | 94.1% | 5 | 12 | 3 | 2 | 13 | 5 |
| 28 | 0.26 | 20 | 0.37 | 0.70 | 2.71 | 1.21 | 88.2% | 8 | 11 | 1 | 2 | 10 | 8 | |||
| Perimeter zone (P3) | 26 | High speed up | 0.34 | 20 | –0.01 | 0.85 | 2.64 | 1.37 | 94.1% | 4 | 14 | 2 | 2 | 10 | 8 | |
| 28 | 0.35 | 21 | 0.08 | 0.73 | 2.81 | 1.24 | 100.0% | 6 | 15 | – | 1 | 14 | 6 | |||
| Overhead diffuser | – | 26 | – | 0.06 | 20 | 0.05 | 0.57 | 1.39 | 1.48 | 89.9% | 8 | 9 | 3 | 2 | 9 | 9 |
[i] Note: The shaded row represents the reference condition test results. The airspeeds column shows the averaged values at 0.1, 0.6 and 1.1 m heights.
AC = air-conditioning; TAV = thermal acceptance vote; TSV = thermal sensation vote.
Figure 5
Density plots for thermal sensation votes (TSVs) under different test conditions.
Note: Shaded areas are the perceived thermally neutral zone with –1 < TSV < +1.
Figure 6
Air movement preference (AP) under different test conditions.
Figure 7
Thermal sensation and acceptability from the human subject tests under the 23°C ambient temperature.
Note: Grey boxes represent the results of reference conditions: the overhead diffuser and the high-side-wall vent with the ceiling fan off. Blue boxes are for fans blowing upward.
Figure 8
Thermal sensation and acceptability from the human subject tests under 28°C ambient temperatures under different fan operation modes.
Note: Grey boxes represent the results of the reference condition: 26°C with an overhead diffuser (high-side-wall vent and ceiling fan off). Lighter blue boxes show the results for a fan downward direction; and darker blue boxes for fan upward direction. The fan level (low or medium) is marked under x-axis; and the two test locations (outside or under the ceiling fan-jet) are mentioned at top.
Figure 9
Thermal sensation and acceptability from the human subject tests at 26°C ambient temperatures with different fan operation modes.
Figure 10
Thermal sensation and acceptable rate from two ceiling fans.
Note: Grey boxes on the left represent the results of the reference condition at neutral ambient temperature. Blue boxes show the results for fan type 1 with a medium upward flow rate. Pink boxes are from fan type 2 with a high upward flow rate. Percentages are acceptability.
Table 4
Comparison of thermal comfort indexes.
| TEST CONDITIONS | WHOLE-BODY THERMAL SENSATION (TSV) | WHOLE-BODY THERMAL ACCEPTANCE RATE (%) | PMV | PPD (%) | PD (%) | SET (°C) | CP VALUES BASED ON EHT (K) | CP VALUES BASED ON SET (K) | |||
|---|---|---|---|---|---|---|---|---|---|---|---|
| LOCATION | TEMPERATURE (°C) | FAN OPERATION MODE | |||||||||
| Fan type 1 | Supply air dumping zone (P1) | 23 | Fan off but AC on | –1.00 | 73.7% | –1.20 | 33.0% | 45.6% | 21.4 | –1.68 | –1.87 |
| Medium up | –0.02 | 85.5% | –0.70 | 14.6% | 24.1% | 23.0 | –0.51 | –0.27 | |||
| 26 | Fan off but AC on | 0.13 | 84.2% | –0.10 | 5.3% | 33.7% | 24.4 | –1.60 | –1.93 | ||
| 28 | Fan off but AC on | 0.28 | 94.4% | 0.60 | 12.5% | 25.7% | 26.4 | –2.32 | –2.00 | ||
| Medium up | 0.93 | 94.4% | 1.00 | 25.9% | 12.8% | 28.1 | –0.32 | –0.34 | |||
| Fan-jet zone (P1’) | 26 | Low down | –0.25 | 89.5% | 0 | 5.0% | 89.6% | 24.2 | –2.08 | –2.20 | |
| 28 | Low down | 0.05 | 100.0% | 0.75 | 17.1% | 65.6% | 26.1 | –2.10 | –2.30 | ||
| Medium down | –0.33 | 94.7% | 0.53 | 10.9% | 98.4% | 25.2 | –4.10 | –3.20 | |||
| Outside the fan zone (P2 or P4) | 23 | Fan off but AC on | –0.32 | 89.5% | –0.38 | 9.1% | 11.0% | 23.6 | 0.23 | 0.25 | |
| Medium up | –0.58 | 89.5% | –0.61 | 13.1% | 23.1% | 23.2 | –0.13 | –0.07 | |||
| 26 | Fan off but AC on | 0.56 | 84.2% | 0.55 | 12.0% | 8.0% | 26.6 | 0.04 | 0.24 | ||
| Low down | 0.38 | 94.7% | 0.27 | 6.7% | 24.8% | 25.6 | –0.81 | –0.71 | |||
| 28 | Fan off but AC on | 1.04 | 77.8% | 1.17 | 34.0% | 5.9% | 28.7 | 0.20 | 0.24 | ||
| Low down | 0.78 | 94.1% | 1.00 | 25% | 18.3% | 27.7 | –0.97 | –0.76 | |||
| Medium down | 0.34 | 100.0% | 0.88 | 21.6% | 33.1% | 26.9 | –1.41 | –1.50 | |||
| Medium up | 0.78 | 84.4% | 1.10 | 28.4% | 12.1% | 28.2 | –0.34 | –0.16 | |||
| Overhead diffuser | – | 26 | – | 0.05 | 89.9% | 0.50 | 10.4% | – | 26.38 | – | – |
[i] Note: The shaded area represents the reference condition test results.
AC = air-conditioning; CP = corrective power; EHT = equivalent homogenous temperature; PMV= predicted mean vote; PD = predicted dissatisfaction due to draft; PPD = predicted percent dissatisfied; TSV = thermal sensation vote.
Figure 11
Comparison of the thermal comfort evaluation indexes.
Figure 12
Local thermal sensations at the face, foot, and hand under different test conditions.
Note: Shaded areas are the thermally neutral zone with –1 < thermal sensation vote (TSV) < +1. To make the plots readable, the local sensations at the forearm and thigh were dropped. For their distributions, see the ‘Extra materials’ sheet in the supplemental data online.
Figure 13
Whole-body thermal sensation changes under different test conditions: (a) acclimation period; and (b) test sessions.
Note: For the acclimation period, the first, second, and third votes correspond to the 10th, 20th, and 30th min, respectively. For test sessions, they correspond to the zero, 10th, and 20th min, respectively. Red dots represent the top three subjects who tend to feel warmer than the others. Blue dots are the top three subjects who tend to feel colder than the others. Black dots and the solid regression lines are the average thermal sensation vote (TSV) from all the subjects.
Figure 14
Locations and operation modes of the high-side-wall vent system.