## CEILING FAN TEST PROCEDURE DEVELOPMENT T ESTING

FINAL REPORT , PART 1:

ENERGY CONSERVATION PROGRAM FOR CONSUMER

PRODUCTS:

Ceiling Fans

October 201 4

U.S. Department of Energy
Assistant Secretary Office of Energy Efficiency and Renewable Energy Building Technologies Program Appliances and Commercial Equipment Standards Washington, DC 20585Th is Document was prepared for the Department of Energy by staff members of

Lawren ce Berkeley National Laboratory

2CEILING FAN TEST PROCEDURE DEVELOPM ENT TESTING

FINAL REPORT , PART 1

TABLE OF CO NTENTS

1. INTRODUCTION ...............................................................................................................5

1.1. Current Test Procedure ...........................................................................................5

1.2. Products Tested ........................................................................................................7

2. USE OF TEST CYLINDER ................................................................................................8

3. USE OF FALSE CEILING ................................................................................................10

4. ACCURACY OF VELOCITY SENSORS ........................................................................13

5. INTERACTIVE EFFECTS OF MULTIPLE FAN HEAD S .............................................15

6. AIRFLOW FROM TILTED FAN HEAD .........................................................................17

7. VERTICAL DISTANCE FROM BLADE TO SENSORS ...............................................19

3LIST OF TABLES

Table 1: Products used in ceiling fan test report. .............................................................................7 Table 2: Air velocity variance without a test cylinder as percentage of the variance with a test cylinder ..............................................................................................................9Table 3: Airflow and power measurements for different test configurations of a multihead fan system. .....................................................................................................16 Table 4: Testing results for an adjustable tilt fan head. .................................................................18 Table 5: Testing results for both vertical distance measurements. ................................................20

LIST OF FIGURE S

Figure 1: Side view of testing room in current test procedure. ........................................................6 Figure 2: Top-down view of testing room and placement of sensor axes in current test procedure..................................................................................................................6 Figure 3: Airflow without test cylinder as percentage of airflow with test cylinder for Fans 1, 2, and 3. .......................................................................................................8 Figure 4: Airflow at all speeds for Fans 4 through 8 with a false ceiling, expressed as a percentage of each fan’s airflow without a false ceiling. .......................................11 Figure 5: Airflow for standard and hugger mount of Fan 9 with false ceiling, expressed as a proportion of the airflow for standard mount without a false ceili ng. ................11 Figure 6: Airflow with a false ceiling as a function of the difference between false ceiling

size and fan diameter for all speeds of hugger Fans 4 through 8. Airflow is expressed as a percentage of each fan’s airflow without a false ceiling. ...............12 Figure 7: Distribution of standard error of air velocity measured at two labs. The dotted

red line indicates the mean of each distribution.....................................................13 Figure 8: Measured standard deviation of Fan 1 air velocity measurements from Lab 2, compared to the standard deviation expected if all of the variation in measurements resulted from the accuracy of the sensors alone. ...........................14 Figure 9: Airflow velocity profiles on high speed for multi-head fan system with both heads turned on simultaneously, and the sum of testing each fan head individually. ...........................................................................................................15 Figure 10: Airflow velocity profile along 4 sensor axes, for an adjustable tilt fan head. Tests were conducted with fan head point straight down, and tilted 15° away from straight down in the directio n of axis C. ..............................................17 Figure 11: Vertical distance test for Fan 2. ....................................................................................19 Figure 12: Vertical distance test for Fan 11. ..................................................................................20

4CEILING FAN TES T PROCEDURE DEVELOPMENT TESTING

FINAL REPORT , PART 1

1. INTRODUCTION

The U.S. Department of Energy (DOE) conducted a series of tests to assess the impact of proposed revisions and additions to the current DOE test procedure for ceiling fans on airflow and power consumption measurements . DOE collected and analyzed data on ai rflow and power consumption for the following topics:

• Impact of using a test cylinder for all ceiling fans

• Impact of using a false ceiling for standard and hugger mount ceiling fans

• Accuracy requirements of air velocity sensors

• The interactive effect of multiple fan heads and the impact of estimating airflow and power using measurements of individual fan heads

• The effects of measuring airflow from a tilted fan head

• Impact of measuring the vertical distance from the middle of the blade tip blades to sensors or the bottom of the blade tip to sensors

1.1. CURRENT TEST PROCEDU RE

In the current DOE test procedure (10 C.F.R. 430, Subpart B, Appendix U) , the ceiling fan is mounted above a test cylinder , as illustrated in Figure 1

, that has a diameter that is 8 inches wider than the ceiling fan blade span. At the bottom of the cylinder, airflow velocity sensors are placed from the center of the cylinder directed radially outward at 4- inch intervals to measure the radial airflow pattern (see Figure 2 ). Measurements of airflow velocity in units of feet per minute are taken by sensors along each ax is and averaged. The total airflow in units of cubic feet per minute (CFM) is calculated as the average air velocity multiplied by the area (in cubic feet) covered by the airflow sensors. The recommended dimensions for the testing chamber are 20 ft. x 20 ft. with

an 11 ft. high ceiling. This test procedure is based on the ENERGY STAR Version 1.1 test procedure for ceiling fans. The current test procedure does not specify a methodology for measuring airflow for hugger mount ceiling fans, tilted fan heads that cannot be pointed directly down, or multi- head fan systems. It also does not specify a procedure for measur ing standby or off mode energy consumption.

5Figure 1 : Side view of testing room in current test procedure

.

Figure 2 : Top

- down view of testing room and placement of sensor axes in current test procedure

.

61.2. PRODUCTS TESTED

Table 1 shows the list of the 11 products along with relevant attributes used in this analysis.

Table 1 : Products used in ceiling fan test report.

Fan

ID Blade Span (inches) Number of Speeds Standard

Mount Hugger

Mount Multi

- Head

Fan Notes

1 44 3 X

2 52 3 X

3 56 3 X

4 44 6 X

5 44 3 X

6 44 4 X

7 52 3 X

8 52 6 X

9 52 3 X X Multi

- mount fan

10 24 3 X Two 24" fan heads

11 52 3 X Curved fan blades

72. USE OF TEST CYLINDER

To determine the effect of the test cylinder, DOE tested Fans 1, 2, and 3 both with and without test cylinders. DOE compared the airflow without the test cylinder to airflow with the test cylinder. Figure 3 shows the airflow without a test cylinder, expressed as a percentage of the airflow with a test cylinder, for all speeds of the three fans. Airflow without a cylinder ranged from 3% lower to 11% higher than the airflow with a cylinder. On average, the airflow without the cylinder was 5% higher than airflow with the cylinder.

Figure 3 : Airflow without test cylinder as percentage of airflow with test cylinder for Fans 1, 2, and 3.

DOE also investigated the variability of the air velocity measurements used to calculate airflow. In the test procedure, 100 air velocity measurements are taken, once per second, at each sensor position and axis. These measurements are then averaged to get a mean a ir velocity at that position and axis. DOE used the variance of the 100 air velocity measurements at each sensor position and axis as a measure of the variability of the air velocity measurements. Table 2 shows the mean variance of the air velocity measurements for each fan without a test cylinder, expressed as a percentage of the variance with a test cylinder. On average, variance without a cylinder was 20% lower than variance with a cylinder.

8Table 2 : Air velocity variance without a test cylinder as percentage of the variance with a test cylinder

Fan Mean air velocity variance without a test cylinder as a percentage of the variance with a test cylinder

Fan 1 66.5 %

Fan 2 87.2 %

Fan 3 85.9 %

93. USE OF FALSE CEILING

DOE tested hugger (aka low profile) ceiling fans and standard mount fans to investigate the use of a false ceiling. In the current test procedure, as shown in Figure 1 , there are over 40 inches of clearance between the ceiling of the testing room and the fan blades. A false ceiling is a board or

other flat surface , suspended from the ceiling of the testing room, to which test fans are mounted. Once mounted to a false ceiling, the clearance between the fan blades and the false ceiling is the

same clearance that the blades would have after installation in a home , typically 15 inches or

less

.

To determine the effect of a false ceiling on hugger fan airflow, DOE tested Fans 4 through 8

wi th and without a false ceiling. (Fan 9 was not tested in the hugger configuration without a false ceiling.) Two different false ceiling sizes, 60 and 68 inches sq uare , were used in the tests. These false ceilings are between 8 -24 inches larger than the ceiling fans tested, depending on the size of

the fans. Figure 4 shows airflow for all speeds of each fan with a false ceiling, expressed as a percentage of airflow without a false ceiling. On average, airflow with a false ceiling was 37%

lower than the ai rflow without a false ceiling.

10Figure 4 : A irflow at all speeds for Fans 4 through 8 with a false ceiling , expressed as a percentage of each fan’s airflow without a false ceiling

.

To determine the effect of a false ce iling on t he airflow of multi -mount fans that can be mounted in standard and hugger configuration , DOE tested the multi -mount Fan 9 in three configurations:

1) standard mount without a false ceiling

2) standard mount with a false ceiling

3) hugger mount with a false ceiling

. Figure 5 shows airflow at all 3 speeds for the two configurations with a false ceiling, expressed as a percentage of airflow for standard mount without a false ce iling. On average, and compared to the standard mount without a false ceiling, the airflow in the standard mount configuration

was 30% lower with a false ceiling , and airflow in the hugger mount configuration was 46%

lower with a false ceiling

. DOE assumed that the airflow of the hugger mount without a false ceiling would be nearly identical to the airflow of the standard mount without a false ceiling,

because the current test procedure requires that the fan blades are in the same position relati ve to
the testing room ceiling and test cylinder for both mounting options.

Figure 5 : Airflow for standard and hugger mount of Fan 9 with false ceiling , expressed as a proportion of the

airflow for standard mount without a fa lse ceiling

.

11To determine the effect of the size of the false ceiling on hugger fan airflow, DOE used two sizes of false ceiling in its tests —60 inches square and 68 inches square. Figure 6 shows the relationship between airflow and the difference in size between the fan and false ceiling for Fans 4 through 8, using the same results shown in Figure 4

. Note that tests at all available speeds are

shown for all fans. There is no clear relationship between airflow and the difference in size between the fan and false ceiling in this sample. In addition, DOE tested Fan 5 with both ceiling

size s, and the mean airflow differed by 3% between the two false ceilings

. These results can be seen in Figure 4.

Figure 6 : A irflow with a false ceiling as a function of the difference between false ceiling size and fan diameter for all speeds of hugger Fans 4 through 8

. Airflow is expressed as a percentage of each fan’s airflow without a false ceiling

.

124. ACCURACY OF VELOCITY SENSORS

To determine whether sensor accuracy affects ceiling fan airflow measurements, DOE used data from Fan 1. DOE first compared the standard error of air velocity measurements from tests of Fan 1 at two test labs. Lab 1 used sensors with accuracy equal to the maximum of 5% of the reading or 1% of the full range of the sensor. Lab 2 used senso rs with accuracy equal to the maximum of 2% of the reading or 0.5% of the selected range of the sensor. Figure 7 shows that

the distribution of standard errors from L ab 1 had a similar ran ge to the distribution from Lab 2,

and the mean standard errors differ ed by approximately 5 feet per minute.

Figure 7 : Distribution of standard error of air velocity measured at two labs. The dotted red line indicates the

mean of each distribution.

13DOE also investigated the variability of the individual air velocity measurements from Lab 2’s

test of Fan 1 . DOE used the assumption that the reported accuracy of the sensors provided an

estimate of a 95% confidence interval for the individual sensor readings. Based on this assumption, DOE calculated the standard deviation of sensor readings that would be expected if

all of the variat ion in measurements resulted from the accuracy of the sensors alone. Figure 8

shows the ratio of the actual measured standard deviation to the standard deviation expected from the sensor accuracy alone. The ratio ranges from 3 to 34, with a mean of 15.

Figure 8 : Measured s tandard deviation of Fan 1 air velocity measurements from Lab 2, compared to the standard deviation expected if all of the variation in measurements resulted from the accuracy of the sensors

alone

.

145. INTERACTIVE EFFECTS OF MULTIPLE FAN HEAD S

DOE conducted test s to measure the interactive effects of a multi

- head fan system. Fan 10 is a

multi -head fan with two 24” fan heads connected by a rod with a center housing that allows for each fan head to be turned on/off individually.

Fan 10 was first tested with the mid point of the fan system centered at the origin of the four sensor axes. The fan heads were oriented along the A -C sensor axis with the fan heads operating simultaneously. In the next test, the fan system was held in the same position and measurements

were taken for each individual head. In instances where only one fan head was being operated, the other fan head was turned off using a switch located on the center housing.

Figure 9 compares the airflow velocity profile on high speed for both heads turned on simultaneously to the sum of testing each fan head individually. The top panel displays the velocity profile along the A -C axis and the bottom panel along the B- D axis. The tests with individual fan heads produce more airflow along the outermost sensors on the A- C axis. With both fan heads operating simultaneously, air is drawn into the center of system, which is also apparent along the B

- D axis

.

Figure 9 : Airflow velocity profiles on high speed for multi

- head fan system with both heads turned on simultaneously, and the sum of testing each fan head individually.

15Table 3 shows the airflow and power measurements for the different test configurations. Compared to the airflow when both fan heads are operating simultaneously, the sum of airflow

measurements from the individual fan head test s is 9% higher on low, 7% higher on medium, and 20% higher on high. These results suggest that interactive effects of multiple fan heads act to

reduce the total measured airflow.

Measurements of power consumption found that tests involving only one operating fan head produced power values that were approximately 75% of the power consumption of both fan heads operating. As shown in Table 3 , summing the power consumption of individual fan heads significantly overestimates the power consumption of the fan system with both fan heads operational by 50% on low, 42% on medium, and 26% on high speed.

Table 3 : Airflow and power measurements for different test configuration s of a multi

- head fan system.

Test Configuration Low Medium High

CFM Power (W) CFM Power (W) CFM Power (W)
Fan Head 1 only 1120.28 14.9 1587.05 25.8 2827.01 49.2
Fan Head 2 only 1004.71 14.9 1650.85 26.0 2682.79 46.4

Fan Head 1 +

Fan Head 2 2124.99 29.8 3237.90 51.8 5509.80 95.5

Both Heads Simultaneously 1957.01 19.9 3012.85 36.3 4607.54 75.7

Percent

Difference * +9% +50% +7% +42% +20% +26%

* Sum of individual fan head measurements compared to both fan heads operating simultaneously.

166. AIRFLOW FROM TILTED FAN HEAD

DOE conducted tests on a tilt -adjustable fan head to measure the impact on airflow when the fan

is directed at an angle other than straight down in the direction of the sensors. For these tests an individual fan head from Fan 10 was mounted directly above the center of the sensor axes (i.e., above sensor 1). In the first test, airflow was measured with the fan head pointed directly down towards the plane of the sensors. Next, the fan head was tilted 15° away from straight down in

the direction of axis C.

Figure 10 shows the airflow velocity profile for both test configurations. The top panel shows the velocity profile along the A -C axis and the bottom panel shows the veloc ity profile along the B

D axis. The overall shapes of the velocity profiles along the A- C axis are similar with the exception that the profile for the tilted fan head is shifted approximately 2 sensor positions along the C axis. Along the B- D a xis, the sensors measure less airflow from the titled configuration compared to the straight down configuration. This is not unexpected since the peak of the airflow for the tilted configuration is offset along the C axis.

Figure 10 : Airflow velocity profile along 4 sensor axes, for an adjustable tilt fan head. Tests were

conduct ed with fan head point straight down, and tilted 15° away from straight down in the direction

of axis C.

17Table 4 shows the total measured CFM averaged over the four sensor axes and summed over sensor positions . Measurements for the tilted configuration are systematically lower compared to the straight d own configuration. In comparison to the straight down configuration, measurements for CFM in the titled configuration are 9% lower on low speed, 17% lower on medium speed, and 6% lower on high speed.

Table 4 : Testing results for an adjustable tilt fan head.

Configuration CFM Low CFM Med CFM High
Straight Down 1149.50 1891.02 3093.20

Tilted 15° 1041.36 1560.61 2904.22

Percent

Difference* - 9%

- 17%

- 6%

* Tilted configuration compared to straight down.

187. VERTICAL DISTANCE FROM BLADE TO SENSORS

Fan 2 and 11 were tested to assess the impact of measuring airflow using a vertical distance measured from the sensors to the bottom of the blade tip compared to a vertical distance measured from the sensors to the middle of the blade tip. Measurements were recorded on low, medium, and high speeds for both vertical distance configurations.

Figure 11 and Figure 12 illustrate the air velocity as a function of sensor position for Fan 2 and Fan 11, respectively. The values for airflow velocity are averaged over the four sensor axes. Results for high speed are in blue, medium speed in green, and low speed in red. Solid lines represent tests where the vertical distance is measured from the sensors to the middle of the blade. Dashed lines represent tests where distance is measured from the sensor to the bottom of

the blade.

Table 5 provides the testing results for the two vertical distance configurations. Shown are the

measured CFM results on low, medium, and high speed for the two fans averaged over all sensor axes and summed over sensor position. Measurements on high and low speeds are consistent to within 3% (with respect to the test where distance is measured to the middle of the blade), while low speed is within 6%.

Figure 11 : Vertical distance test for F an 2.

19Figure 12 : Vertical distance test for F an 11.

Table 5 : Testing results for both vertical distance measurements.

Fan ID Vertical Distance

Measured from CFM Low CFM Medium CFM High

2 Middle of Blade 1882.21 3199.15 4407.43

Bottom of Blade 1768.73 3105.79 4313.46

11 Middle of Blade 1255.53 2078.14 3339.00

Bottom of Blade 1260.80 2023.25 3321.05

20