task - surround - ambient lighting
TRANSCRIPT
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Task – Surround –Ambient LightingPeter Ngai, PE, LC, FIESAcuity Brands Lighting
April 27th, 2016
Abstract:Task –Ambient lighting provides energy saving but space surrounding the users can be dim and uninviting. This study researched into the proposal of an additional Surround Layer of light. That is, Task-Surround-Ambient system. It examined in a simulated environment, illumination requirements, dimensionality and appearance of the space by the use of Vector/Scalar and Task/Vertical Illumination Ratios. They were evaluated under several illuminance requirements, different Task-Surround proportion combinations and various sources sizes of Surround Light. The results showed that by adding a Surround Light Layer, visual quality of space surrounding the users can be enhanced. Energy savings were also valuated under various illuminance conditions and physical layouts. They showed that Task-Surround-Ambient system achieves energy savings.
LEARNING OBJECTIVES:
Identify the strength and weaknesses of Total Ambient and Task-Ambient Lighting, and introduce the concept of Task- Surround – Ambient Lighting
Create an analytic model and introduce the lighting metrics for lighting comparisons
Compare Lighting Quality of Total Ambient, Task-Ambient and Task- Surround – Ambient Lighting
Compare Energy Savings for Total Ambient, Task-Ambient and Task- Surround – Ambient Lighting
Practical implementations of Task- Surround – Ambient Lighting
Lighting quality: glare-free & uniformly illuminated, reduced dimensionality and personalization
40 fc total @ desktop
Ambient Lighting
40 fc from ambient lighting
Lighting quality: low energy costs with high horizontal workplane illumination, but lower visibility of vertical elements or faces, less dimensionality and sharper shadows. Space rendered dingy and uninviting
Low Ambient –Task Lighting
30 fc from task lighting
10 fc fromAmbient lighting
40 fc total @ desktop
Lighting quality: added layer of surround light for dimensionality and interaction. Enhance the visual quality of the immediate space surrounding the users
SURROUND LIGHTING
10 fc from Ambient lighting
40 fc total @desktop
Low Ambient –Surround –Task lighting Solution
30 fc from surround +Task lighting
This Presentation is a conceptual comparison of Task –Surround –Ambient Lighting System
to Total Ambient and Task-Ambient Lighting Systems
In a Simulated Environment
The Analytic Model
Room Size: 32’ X 32’X 10’ 80%, 50% and 20% reflectancePersonal Space: 8’X 8’X5’ a work station in the middle of the room Task Area : 4’ diameter and 2.5’high with 50% reflectance circular table
Light sources: 4” X 4” diffuser panels for all three separate layers of lighting. Luminous intensity level for each layers adjusted separately
Ambient Lighting Layer -225 panels spaced evenly Surround Lighting Layer - 2’x2’ grid of 25 diffusers at 6’ height over the desk Task Lighting Layer - 21 diffusers mounted at 6” above the task surface It should be understood that the use of 4” X 4” luminous panels and the layouts of the panels were to reduce the analytic complexity. The luminous panels for task lighting layer were treated as photometric entities, and not as solid objects.
Lighting Layouts
Ambient Lighting layer
Surround Lighting layer
Task Lighting layerTask Surface
5 FT
10 F
TPhysical Layout of the Simulated Space
6 FT
8 FT
Lighting Criteria
Low Ambient illumination = 100 Lux
Task illumination @ desktop = 400 Lux
Two location points were analyzed:
1st Point - 10 inches away from the edge of the table and 4ft-2in from the floor.
2nd Point - center of the space at the same height
Center Location PointSide Location Point
Physical Layout of the Simulated Space
20 in
Lighting criteria were evaluated by two factors:1)The ratio of Vertical Illumination @ two location points facing the center of
personal space to that of task surface illumination needs to be within a ratio of 1:3 or better. That is, lower than 1:3
2) The points need to have acceptable Vector/Scalar Illumination ratios 1> V/S <2
Lighting Criteria
Vector/Scalar Ratio Flow of Light Appearance
3.5 Dramatic Theatrical3.0 Very Strong Strong Contrast, Details not discernable
2.5 Strong Suitable for display, too harsh for faces
2.0 Moderately Strong Pleasant for distant face
1.5 Moderately Weak Pleasant for near faces
1.0 Weak Soft Lighting for subdued effects
.5 Very Weak Flat, shadow free lighting
Lighting Effects at Different Vector/Scalar Ratios
Note: Values within bracket should not be ranked in terms of desirability. It is a matter of personal preference/application. CR 1:3 or 1<V/S<2.0 should not be taken literally
(Dimensionality)
Let E(x) and E(-x) be the two opposing Illumination on the X axis E(y) and E(-y) be the two opposing Illumination on the Y axis E(z) and E(-z) be the two opposing Illumination on the Z axis
Then, ʽE(x) = E(x) - E(-x) is the Illumination Vector on the X axis
ʽE(y) = E(y) - E(-y) is the Illumination Vector on the Y axis
ʽE(z) = E(z) - E(-z) is the Illumination Vector on the Z axis
|E|= √(ʽE(x) 2 + ʽE(y)
2 + ʽE(z) 2 ) (1)
The Scalar Illumination Esr , Esr = |E|/4 + (~E(x) + ~E(y) + ~E(z) )/3 (2)
Where ~E(x) is the lesser of E(x) and E(-x)
~E(y) is the lesser of E(y) and E(-y)
~E(z) is the lesser of E(z) and E(-z)
From Equation (1) and (2), Vector/Scalar Ratio = |E|/ Esr
Magnitude of the illumination Vector,
Vector/Scalar Ratio Calculation
Scenario Ambient Layer
Surround Layer
Task Layer
Total Ambient (LUX) 1 400 0 0
Lighting Scenarios
Scenario Ambient Layer
Surround Layer
Task Layer
Task-Ambient (LUX) 2 100 0 300
Lighting Scenarios
Scenario Ambient Layer
Surround Layer
Task Layer
Task-Surround-Ambient
(LUX)
3 100 100 2004 100 150 1505 100 200 100
Lighting Scenarios
Scenario Ambient Layer
Surround Layer
Task Layer
Surround –Ambient (LUX) 6 100 300 0
Lighting Scenarios
Scenario Ambient Layer
Surround Layer
Task Layer
Total Ambient 1 400 0 0
Task-Ambient 2 100 0 300
Task-Surround-Ambient
3 100 100 2004 100 150 1505 100 200 100
Surround –Ambient 6 100 300 0
6 Lighting Scenarios
Results Analysis
Scenario 1E (x) 227 E (-x) 220 ʽE(x) 7 ~E(X) 220 E (x) 245 E (-x) 139 ʽE(x) 106 ~E(x) 139E (y) 212 E (-y) 227 ʽEy) -15 ~E(Y) 212 E (y) 196 E (-y) 207 ʽE(y) -11 ~E(y) 196E (z) 476 E (-z) 128 ʽE(z) 348 ~E(Z) 128 E (z) 445 E (-z) 104 ʽE(z) 341 ~E(z) 104
Vector (Mag) 348 E (Vert) 227 Vector (Mag) 357 E (Vert) 245Scalar 274 E(Horz) 400 Scalar 236 E(Horz) 400
V/S 1.27 CR 1.76 V/S 1.52 CR 1.63Scenario 2
E (x) 73 E (-x) 70 ʽE(x) 3 ~E(X) 70 E (x) 82 E (-x) 39 ʽE(x) 43 ~E(x) 39E (y) 70 E (-y) 71 ʽE(y) -1 ~E(Y) 70 E (y) 54 E (-y) 57 ʽE(y) -3 ~E(y) 54E (z) 120 E (-z) 110 ʽE(z) 10 ~E(Z) 110 E (z) 113 E (-z) 41 ʽE(z) 72 ~E(z) 41
Vector (Mag) 10 E (Vert) 73 Vector (Mag) 84 E (Vert) 82Scalar 86 E(Horz) 400 Scalar 66 E(Horz) 400
V/S 0.12 CR 5.5 V/S 1.28 CR 4.88Scenario 3
E (x) 118 E (-x) 112 ʽE(x) 6 ~E(x) 112 E (x) 146 E (-x) 51 ʽE(x) 95 ~E(x) 51E (y) 118 E (-y) 115 ʽE(y) 3 ~E(y) 115 E (y) 70 E (-y) 73 ʽEy) -3 ~E(y) 70E (z) 453 E (-z) 115 ʽE(z) 338 ~E(z) 115 E (z) 163 E (-z) 49 ʽE(z) 114 ~E(z) 49
Vector (Mag) 338 E (Vert) 118 Vector (Mag) 148 E (Vert) 146Scalar 199 E(Horz) 400 Scalar 94 E(Horz) 400
V/S 1.70 CR 3.39 V/S 1.58 CR 2.74Scenario 4
E (x) 142 E (-x) 132 ʽE(x) 10 ~E(X) 132 E (x) 178 E (-x) 56 ʽE(x) 122 ~E(x) 56E (y) 143 E (-y) 137 ʽEy) 6 ~E(Y) 137 E (y) 75 E (-y) 78 ʽEy) -3 ~E(y) 75E (z) 632 E (-z) 115 ʽE(z) 517 ~E(Z) 115 E (z) 184 E (-z) 52 ʽE(z) 132 ~E(z) 52
Vector (Mag) 517 E (Vert) 142 Vector (Mag) 180 E (Vert) 178Scalar 257 E(Horz) 400 Scalar 106 E(Horz) 400
V/S 2.01 CR 2.82 V/S 1.70 CR 2.25Scenario 5
E (x) 172 E (-x) 158 ʽE(x) 14 ~E(X) 158 E (x) 219 E (-x) 62 ʽE(x) 157 ~E(x) 62E (y) 174 E (-y) 165 ʽEy) 9 ~E(Y) 165 E (y) 83 E (-y) 86 ʽEy) -3 ~E(y) 83E (z) 856 E (-z) 118 ʽE(z) 738 ~E(Z) 118 E (z) 210 E (-z) 58 ʽE(z) 152 ~E(z) 58
Vector (Mag) 738 E (Vert) 172 Vector (Mag) 219 E (Vert) 219Scalar 332 E(Horz) 400 Scalar 122 E(Horz) 400
V/S 2.23 CR 2.33 V/S 1.79 CR 1.83Scenario 6
E (x) 228 E (-x) 206 ʽE(x) 22 ~E(X) 206 E (x) 293 E (-x) 73 ʽE(x) 220 ~E(x) 73E (y) 230 E (-y) 218 ʽEy) 12 ~E(Y) 218 E (y) 97 E (-y) 100 ʽEy) -3 ~E(y) 97E (z) 1273 E (-z) 112 ʽE(z) 1161 ~E(Z) 112 E (z) 258 E (-z) 68 ʽE(z) 190 ~E(z) 68
Vector (Mag) 1161 E (Vert) 228 Vector (Mag) 291 E (Vert) 293Scalar 469 E(Horz) 400 Scalar 152 E(Horz) 400
V/S 2.48 CR 1.75 Scalar 1.91 CR 1.37
Ambient 400 Surround 0 Task 0
Ambient 100 Surround 0 Task 300
Ambient 100 Surround 100 Task 200
Ambient 100 Surround 150 Task 150
Ambient 100 Surround 200 Task 100
Ambient 100 Surround 300 Task 0
Center Location Point Side Location Point
Data on Computations of Illumination, Contrast Ratio and Vector/Scalar Ratios for Task Surface Illumination of 400 Lux
1:1.8 1:1.61:4.9
1:3.9 1:2.7
1:2.8 1:2.2
1:2.3 1:1.8
1:1.8 1:1.4
1:5.5
What can we tell from the above results?
1:1.8 1:1.61:4.9
1:3.9 1:2.7
1:2.8 1:2.2
1:2.3 1:1.8
1:1.8 1:1.4
1:5.5
1:1.8 1:1.61:4.9
1:3.9 1:2.7
1:2.8 1:2.2
1:2.3 1:1.8
1:1.8 1:1.4
1:5.5
Why?
E2(X)E1(X)
E1(X) @ Side Location Pt >
E2(X) @ Center location Pt
Total Ambient and Task - Ambient
E2(X)E1(X)
Task-Surround-Ambient
E1(X) @ Side Location Pt >
E2(X) @ Center location Pt
Why?
SSS
1:1.8 1:1.61:4.9
1:3.9 1:2.7
1:2.8 1:2.2
1:2.3 1:1.8
1:1.8 1:1.4
1:5.5
E1(+X)
E2(+Z)
V/S @ Side Location Pt >
V/S @ Center location Pt
E2(-Z)
E2(-X) E2(+X)
Total Ambient and Task - Ambient
E1(-X)
E1(+Z)
E1(-Z)
ʽE(x) = E(x) - E(-x)
ʽE(z) = E(z) - E(-z)
|E|= √(ʽE(x) 2 + ʽE(z)
2 )
|E1| |E2|>
1:1.8 1:1.61:4.9
1:3.9 1:2.7
1:2.8 1:2.2
1:2.3 1:1.8
1:1.8 1:1.4
1:5.5
Why?
E1(+X)
E2(+Z)
V/S @ Side Location Pt
V/S @ Center location Pt
E2(-Z)
E2(-X) E2(+X)
Task-Surround -Ambient
E1(+Z)
E1(-Z)
ʽE(x) = E(x) - E(-x)
ʽE(z) = E(z) - E(-z)
|E|= √(ʽE(x) 2 + ʽE(z)
2 )
|E1| |E2|
Scenario Side Location Point Center Location Point3 Vector 14.84 33.81
Scalar 9.38 19.85V/S 1.58 1.70
4 Vector 17.98 51.71Scalar 10.59 25.73V/S 1.70 2.01
5 Vector 21.85 73.82Scalar 12.23 33.15V/S 1.79 2.23
6 Vector 29.07 116.13Scalar 15.20 46.90V/S 1.91 2.48
Total Ambient Vs Task - Ambient Lighting at 400 lux Task Surface Illumination
What can we tell from the above results?
Ambient 400 Ambient 100Task 300
0
50
100
150
200
250
300
Vertical Illumination
Center Side
Ambient 400 Ambient 100Task 300
0.000.200.400.600.801.001.201.401.60
Vector/Scalar ratio
Center Side
Total Ambient Vs Task - Ambient Lighting at 400 lux Task Surface Illumination
• Total ambient lighting is better in meeting criteria than task- ambient lighting for both vertical illumination contrast and V/S ratios. This is typical general lighting system that normally found in an open office or a classroom.
Ambient 400 Ambient 100Task 300
050
100150200250300
Vertical Illumination
Center Side
Ambient 400 Ambient 100Task 300
0.00
0.50
1.00
1.50
2.00
Vector/Scalar ratio
Center Side
•Task – ambient lighting appeared to be dingy and dark. The contrast ratios is well below 3:1. While the V/R ratio for the side location point is acceptable, the low illumination renders the condition to be uninviting and dark.
Ambient 400 Ambient 100Task 300
Ambinet 100Surround 300
0
50
100
150
200
250
300
350Vertical Illumination
Center Side
Ambient 400 Ambient 100Task 300
Ambient 100 Surround 300
0.00
0.50
1.00
1.50
2.00
2.50
3.00Vector/Scalar Ratio
Center Side
Total Ambient Vs Task-Ambient Vs Surround- Ambient at 400 lux Task Surface Illumination
What can we tell from the above results?
Ambient 400 Ambient 100Task 300
Ambinet 100Surround 300
050
100150200250300350 Vertical Illumination
Center Side
Ambient 400 Ambient 100Task 300
Ambient 100 Surround 300
0.000.501.001.502.002.503.00 Vector/Scalar Ratio
Center Side
Total Ambient Vs Task-Ambient Vs Surround- Ambient at 400 lux Task Surface Illumination
• The vertical illumination was high and well within the 1:3 contrast ratio. This resulted in brightening up of the entire personal space.
• V/R ratios were high. it drastically increased the dimensionality. In fact, some individuals might find V/S ratio of 2.5 at Center Location Position as too high.
• Side Location point has higher Vertical Illumination and low CR.
Amb 400Sur 0Tsk 0
Amb 100Sur 0
Tsk 300
Amb 100Sur 100Tsk 200
Amb 100Sur 150 Tsk 150
Amb 100 Sur 200Tsk 100
Amb 100Sur 300
Tsk 0
0
50
100
150
200
250
300
350 Vertical Illumination
Center Side
Lighting comparisons for Surround Lighting Layer @400 Lux Task Surface Illumination for different ambient/surround/task light levels
What can we tell from the above results?
Amb 400Sur 0Tsk 0
Amb 100Sur 0
Tsk 300
Amb 100Sur 100Tsk 200
Amb 100Sur 150 Tsk 150
Amb 100 Sur 200Tsk 100
Amb 100Sur 300
Tsk 0
0
50
100
150
200
250
300
350
Vertical Illumination
Center Side
Lighting comparisons for Surround Lighting Layer @400 Lux Task Surface Illumination for different ambient/surround/task light levels
•The higher was the surround light contribution, the higher was the vertical illumination•Contrast ratios from all combinations were better than 1:3 once the combination of Ambient/Surround/Task ratio reached 100/100/200
Amb 400Sur 0Tsk 0
Amb 100Sur 0
Tsk 300
Amb 100Sur 100Tsk 200
Amb 100Sur 150 Tsk 150
Amb 100 Sur 200Tsk 100
Amb 100Sur 300
Tsk 0
0.00
0.50
1.00
1.50
2.00
2.50
3.00
Vector/Scalar Ratio
Center Side
Lighting comparisons for Surround Lighting Layer @400 Lux Task Surface Illumination for different ambient/surround/task light levels
What can we tell from the above results?
Amb 400Sur 0Tsk 0
Amb 100Sur 0
Tsk 300
Amb 100Sur 100Tsk 200
Amb 100Sur 150 Tsk 150
Amb 100 Sur 200Tsk 100
Amb 100Sur 300
Tsk 0
0.00
0.50
1.00
1.50
2.00
2.50
3.00
Vector/Scalar Ratio
Lighting comparisons for Surround Lighting Layer @400 Lux Task Surface Illumination for different ambient/surround/task light levels
• v/s ratios from all combinations were between 1 and 2 once the combination of Ambient/Surround/Task ratio reached 100/100/200.
• Contrast ratios moved higher as surround lighting contribution increases.
• The results showed that with a wide range of adjustments for task and surround lighting layers, a user could achieve a satisfactory lighting condition for his/her preference.
Effect of Task Surface Illumination Levels
Amb 200Sur 0Tsk 0
Amb 100Sur 0
Tsk 100
Amb 100Sur 33Tsk 67
Amb 100Sur 50Tsk 50
Amb 100 Sur 67Tsk 33
Amb 100Sur 100
Tsk 0
020406080
100120140160
Center Side
Amb 400Sur 0Tsk 0
Amb 100Sur 0
Tsk 300
Amb 100Sur 100Tsk 200
Amb 100Sur 150 Tsk 150
Amb 100 Sur 200Tsk 100
Amb 100Sur 300
Tsk 0
0
50
100
150
200
250
300
350Vertical Illumination
Center Side
What can we tell from the
results?
400 Lux
300 Lux 200 Lux
Effect of Task Surface Illumination Levels
Amb 200Sur 0Tsk 0
Amb 100Sur 0
Tsk 100
Amb 100Sur 33Tsk 67
Amb 100Sur 50Tsk 50
Amb 100 Sur 67Tsk 33
Amb 100Sur 100
Tsk 0
020406080
100120140160 Vertical Illumination
Center Side
Amb 400Sur 0Tsk 0
Amb 100Sur 0
Tsk 300
Amb 100Sur 100Tsk 200
Amb 100Sur 150 Tsk 150
Amb 100 Sur 200Tsk 100
Amb 100Sur 300
Tsk 0
0
50
100
150
200
250
300
350 Vertical Illumination
Center Side
• Trends for CR were the same as that at 400 lux. The higher was the surround lighting portion, the higher was the vertical illumination and V/S ratio.
• For scenarios involving surround lighting layer, similar to 400 lux task surface illumination case, the side location points had higher vertical illumination.
• When comparing across task surface illumination levels, the lower was task surface illumination, the more the values moved towards compliance. The reason was that at lower surface illumination level, Ambient Lighting Layer that was held to a constant value, contributed a larger proportion of the total task surface illumination.
400 Lux 300 Lux 200 Lux
300 Lux
Effect of Task Surface Illumination Levels
Amb 200Sur 0Tsk 0
Amb 100Sur 0
Tsk 100
Amb 100Sur 33Tsk 67
Amb 100Sur 50Tsk 50
Amb 100 Sur 67Tsk 33
Amb 100Sur 100
Tsk 0
0.0
0.5
1.0
1.5
2.0
2.5
Center Side
Amb 400Sur 0Tsk 0
Amb 100Sur 0
Tsk 300
Amb 100Sur 100Tsk 200
Amb 100Sur 150 Tsk 150
Amb 100 Sur 200Tsk 100
Amb 100Sur 300
Tsk 0
0.0
0.5
1.0
1.5
2.0
2.5
3.0Vector/Scalar Ratio
Center Side
What can we tell from the results?
400 Lux
200 Lux
Effect of Task Surface Illumination Levels
• When comparing across task surface illumination levels, the lower was task surface illumination, the more C/S values moved towards compliance. The reason was the same as Vertical Illumination
Amb 400Sur 0Tsk 0
Amb 100Sur 0
Tsk 300
Amb 100Sur 100Tsk 200
Amb 100Sur 150 Tsk 150
Amb 100 Sur 200Tsk 100
Amb 100Sur 300
Tsk 0
0.0
0.5
1.0
1.5
2.0
2.5
3.0
Amb 200Sur 0Tsk 0
Amb 100Sur 0
Tsk 100
Amb 100Sur 33Tsk 67
Amb 100Sur 50Tsk 50
Amb 100 Sur 67Tsk 33
Amb 100Sur 100
Tsk 0
0.0
0.5
1.0
1.5
2.0
2.5
VECTOR/SCALAR
• All 3 combinations of Ambient /Surround/Task location points for all three light levels within the acceptable range both in terms of Illumination Contrast Ratios and V/S ratios.
• Trends in V/S same as that at 400 lux. The higher was the surround lighting, the higher was V/S.
• Similar to 400 lux task surface illumination case, the side location points had lower V/S ratio.
• The results showed that the concept of Task-Surround-Ambient worked for a wide range of task surface illumination.
Effect of Surround Lighting Layer Size
Vertical IlluminationSide Location Point
Vertical IlluminationCenter Location Point
What can we tell from the above results?
Equal Light Output
E1(X) E2(X)
E1(X) < E2(X)
Vertical Illumination Center Location Point
For center point location, Larger size, greater Vertical Illumination, why?
Equal Light Output
E1(X) E2(X)E1(X) ≈ E2(X)
Vertical Illumination Side Location Point
Side point location, different sizes, similar Vertical Illumination, why?
Effect of Surround Lighting Layer Size
Vertical IlluminationSide Location Point
Vertical IlluminationCenter Location Point
• For center location point, the larger was the size of surround light source, the greater was the vertical illumination.
• For side location point, different surround light source sizes did not affect Vertical Illumination appreciably.
• For center location point, the more surround light, the more was the vertical illumination.
• For side location point, the more is surround light, the greater was the vertical illumination.
Effect of Surround Lighting Layer Size
What can we tell from the above results?
Vector/Scalar RatioCenter Location Point
Vector/Scalar RatioSide Location Point
Equal Light Output
E1(Z) E2(Z)
V/S(1) > V/S(2)
E1(Z) > E2(Z)
Vector/Scalar Ratio Center Location Point
For center point location, smaller size, greater Vertical Illumination, why?
Equal Light Output
E1(Z)E2(Z)
E1(Z) ≈ E2(Z)
V/S(1 ≈ V/S(2)
Vector/Scalar Ratio Side Location Point
Side point location, different sizes, similar Vertical Illumination, why?
Effect of Surround Lighting Layer Size
Vector/Scalar RatioCenter Location Point
Vector/Scalar RatioSide Location Point
• For center location point, the smaller was the area of the Surround Lighting layer, the higher was the V/R ratio.
• For center location point, the more was surround light, the greater was the V/R ratio.• For side location point, different surround light source sizes did not affect V/R appreciably.
• For side location point, the more surround light, the greater was the V/R ratio.
Effect of Surround Lighting Layer Size
1. Smaller surround light size, creates greater luminance and high V/R ratio. This produces glary, hash and dramatic lighting environment. Not a good approach for surround lighting layer. As the surround source size increases, luminance intensity reduces and the environment gets softer and more comfortable.
2. Results and assertions from task surface illumination of 400 lux can be extended to lower task surface illumination level. When the overall task surface illumination is lowered, the proportion of ambient lighting layer contribution to task surface illumination increases. This will pull the results closer to that of the ambient only system. Hence, at lower task illumination, various sizes of Surround Lighting Layer will behave similarly to that of at 400 lux and with more ease of compliance.
5, 9 and 12-Stations Layout
Relative Energy Consumptions
Relative Energy Consumptions
What can we tell from the above results?
Amb 400
Sur 0Tsk 0
Amb 100
Sur 0 Tsk 300
Amb 100Sur 100Tsk
200
Amb 100Sur 150 Tsk 150
Amb 100 Sur 200Tsk 100
Amb 100Sur 300
Tsk 0
Amb 300
Sur 0Tsk 0
Amb 100
Sur 0 Tsk 200
Amb 100
Sur 67Tsk 133
Amb 100Sur 100 Tsk 100
Amb 100 Sur 133
Tsk 67
Amb 100Sur 200
Tsk 0
Amb 200
Sur 0Tsk 0
Amb 100
Sur 0 Tsk 100
Amb 100
Sur 37Tsk 67
Amb 100
Sur 50 Tsk 50
Amb 100
Sur 67Tsk 33
Amb 100Sur 100
Tsk 0
0.00
0.20
0.40
0.60
0.80
1.00
1.20
5 Workstations 9 Workstations 12 Workstations
400 lux 300 lux 200 lux
Relative Energy Consumptions
• As the proportion of surround light increased, the energy savings decreased.
Amb 400
Sur 0Tsk 0
Amb 100
Sur 0 Tsk 300
Amb 100
Sur 100Tsk 200
Amb 100
Sur 150 Tsk 150
Amb 100
Sur 200Tsk 100
Amb 100
Sur 300Tsk 0
Amb 300
Sur 0Tsk 0
Amb 100
Sur 0 Tsk 200
Amb 100
Sur 67Tsk 133
Amb 100
Sur 100 Tsk 100
Amb 100
Sur 133Tsk 67
Amb 100
Sur 200Tsk 0
Amb 200
Sur 0Tsk 0
Amb 100
Sur 0 Tsk 100
Amb 100
Sur 37Tsk 67
Amb 100
Sur 50 Tsk 50
Amb 100
Sur 67Tsk 33
Amb 100
Sur 100Tsk 0
0.000.200.400.600.801.001.20
5 Workstations 9 Workstations 12 Workstations400 lux 300 lux 200 lux
• Total Ambient Lighting had the highest energy consumption for all three workstation layouts and all lighting scenarios. Task – Ambient Lighting consumed the least.
• The higher was the task surface illuminance, the higher was the relative energy savings. This was true for all lighting scenarios.
• The lower was the density of workstations, the higher was the energy savings. • Energy savings for Task-Surround-Ambient lighting system compared favorably with Task-Ambient
system. This was especially true in case of high task surface illumination and low density workstation layout.
Implementing Low Ambient –Surround –Task lighting Solutions
Implementing Low Ambient –Surround –Task lighting Solutions
Implementing Low Ambient –Surround –Task lighting Solutions
• The addition of surround lighting layer is effective in enhancing dimensionality and the appearance of space over and beyond what Task-Ambient Lighting can offer.
• This is valid though a range of task surface illumination and surround light source sizes.
• The study also taught the idea of adjusting to different combinations of Task and Surround Lighting Layers which allows the user to tune to for different lighting applications as well as personal preferences.
• This study showed energy savings for Task- Surround – Ambient Lighting compared favorably to that of Task-Ambient Lighting system.
Conclusions
• The study was anchored with two lighting measures. illumination ratio and the Vector/Scalar Ratio The first criterion is straight forward and generally accepted. As for the second criterion, there are a number of other models including, Cylindrical /Horizontal Illumination Ratio, Vector/Cylindrical Illumination Ratio and Target/Ambient illumination Ratio (TAIR) among others. Vector/Scalar Ratio is probably the most recognized metric. Hence this study adopted this criterion. While other metrics will yield different numeric results, but the essences and trends investigated by this study using Vector/Scalar should be similar.
• This study was based on a specific set of lighting conditions. Different sets of input will not replicate identical numeric values. However, this should not alter the fundamental results and conclusions of this study. The main trust of this paper is to gain insight of the interplay among the three layers of light. Hence, the study should be viewed in a conceptual perspective rather than quantitative precision. When a specific lighting layout is known, then the lighting can be evaluated for that specific condition.
Discussions
• The results of this paper is not limited to facial modeling. It is valid to extend to appearance of any objects within the personal space. Hence Task - Surround concept is just as applicable with multiple persons interacting within the space, as with a single person working in solitude.
• It is important to point out that this study focused on the visual appearance surrounding the task area by means of Contrast Ratio and Vector/Scalar Ratio. Other important lighting quality factors such as task visibility, visual comfort, and health and wellbeing aspects though not the subject of our study, should always be considered.
• Final, while the study was done with three discrete layers of lighting for clarity, in practice, it is conceivable that one luminaire through its light distributions and positioning, can function as more than one layer of light.
Discussions
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