# Dynamic Daylight Metrics for Electricity Savings in Offices: Window Size and Climate Smart Lighting Management

^{1}

^{2}

^{*}

## Abstract

**:**

## 1. Introduction and Objectives

#### 1.1. State of the Art

#### 1.2. Aim and Objectives

## 2. Description of Methodology for Calculation

#### 2.1. Characteristics of the Room Model

#### 2.1.1. Geometry of the Room Model

#### 2.1.2. Location of the Room Model

- Stockholm (Sweden): 60° north latitude, mainly overcast skies.
- London (UK): 50° north latitude, predominantly overcast skies.
- Madrid (Spain): 40° north latitude, mainly clear skies.

#### 2.1.3. Orientation of the Window

#### 2.2. Lighting Design of the Room Model

- Case study 1: Manual On/Off lighting control with two separate control rows: circuit 1 is for the near-façade lighting row and a second command control is for the remaining lighting rows. This system is only available for rooms 6 and 9 m deep.
- Case study 2: Common Dimming lighting control for all the luminaires of the room (single controller). The dimmer is controlled by a lux-meter which detects daylight illuminance, adjusting the power supply for the lamps.
- Case study 3: Two independent dimming-lighting-controls with two separate groups, where one circuit commands the near-façade lighting line and the other the remaining lighting rows. Systems are controlled by lux-meters which detect daylight illuminance, adjusting the power supply for the lamps. This system is only available for rooms 6 and 9 m deep.

^{2}/100 lx for bright rooms and 1.7 W/m

^{2}/100 lx for dark rooms. In the case of halogen or fluorescent lamps, the energy efficiency would be noticeably poorer, consuming more energy than the luminaires selected. Therefore, LED lamps represent the most conservative scenario for calculating the suitability of smart controls.

#### 2.3. Parameters of the Calculation Program

#### 2.4. Calculation Metrics

#### 2.4.1. Daylight Metrics and Conditions

#### 2.4.2. Cost-Effectiveness Metrics and Conditions

- n is the Project horizon (a maximum of 10 years is considered a reasonable lifetime for LED lighting systems for office buildings (50,000 h);
- i is the Year of the study;
- FB
_{i}is the Flow of benefits obtained in the year i (due to the savings in the annual electricity bill); - E
_{s}is Annual electric energy saving for each hypothesis, in kW·h; - EC
_{i}is the Annual electric energy cost for each country [51], in €/(kW·h); - AGR
_{E}is the Annual Growth Rate of the electric energy cost for each country.

_{i}), affected by the national price of electric energy and its fluctuations, is difficult to predict, especially when a period of 10 years is considered (NPV

_{10}). This is because the Annual electric energy cost used here was that of 2016 and the Annual Growth Rate of the electric energy cost (AGR

_{E}) was calculated from the annual electricity prices from 2005 to 2016 for each country under study, according to EUROSTAT [51]. Both EC and EC

_{i}for each country under study are shown in Table 4:

## 3. Validation of the Calculation Program and the Dynamic Metrics

#### 3.1. Characteristics of the Test Cell for Validation Process

#### 3.2. Calculation Model for Validation Process

#### 3.3. Calculation and Measurement Conditions of Validation Process

#### 3.4. Analysis of Validation Process Results

## 4. Calculations

#### 4.1. Quantification of Power Consumption in Stockholm

^{2}according to case studies 0 (On/Off control for all luminaires), 1 (On/Off control with two separate lines), 2 (Dimming control for all luminaires), and 3 (Dimming control with two separate lines).

#### 4.2. Quantification of Power Consumption in London

^{2}for each Case study.

#### 4.3. Quantification of Power Consumption in Madrid

^{2}, based on the case studies.

## 5. Analysis of Payback Period and Net Present Value

#### 5.1. Cost Effectiveness in Stockholm

#### 5.2. Cost Effectiveness in London

#### 5.3. Cost Effectiveness in Madrid

## 6. Conclusions

## Author Contributions

## Funding

## Acknowledgments

## Conflicts of Interest

## References

- Ryckaert, W.; Lootens, C.; Geldof, J.; Hanselaer, P. Criteria for energy efficient lighting in buildings. Energy Build.
**2010**, 42, 341–347. [Google Scholar] [CrossRef] - Lam, J.C.; Li, D.H.W.; Cheung, S.O. An analysis of electricity end-use in air-conditioned office buildings in Hong Kong. Energy Build.
**2003**, 38, 493–498. [Google Scholar] [CrossRef] - Armaroli, N.; Balzani, V. Towards an electricity-powered world. Energy Environ. Sci.
**2011**, 4, 3193–3222. [Google Scholar] [CrossRef] - Acosta, I.; Munoz, C.; Campano, M.A.; Navarro, J. Navarro, Analysis of daylight factors and energy saving allowed by windows under overcast sky conditions. Renew. Energy
**2015**, 77, 194–207. [Google Scholar] [CrossRef] - ul Haq, M.A.; Hassan, M.Y.; Abdullah, H.; Rahman, H.A.; Abdullah, M.P.; Hussin, F.; Said, D.M. A review on lighting control technologies in commercial buildings, their performance and affecting factors. Renew. Sustain. Energy Rev.
**2014**, 33, 268–279. [Google Scholar] [CrossRef] - Fernandes, L.L.; Lee, E.S.; DiBartolomeo, D.L.; McNeil, A. Monitored lighting energy savings from dimmable lighting controls in The New York Times Headquarters Building. Energy Build.
**2014**, 68, 498–514. [Google Scholar] [CrossRef] [Green Version] - Li, D.H.; Cheung, A.C.; Chow, S.K.; Lee, E.W. Study of daylight data and lighting energy savings for atrium corridors with lighting dimming controls. Energy Build.
**2014**, 72, 457–464. [Google Scholar] [CrossRef] - Lee, N.; Kim, J.; Jang, C.; Sung, Y.; Jeong, H. Comparison of sensorless dimming control based on building modeling and solar power generation. Energy
**2015**, 81, 15–20. [Google Scholar] [CrossRef] - Ochoa, C.E.; Aries, M.B.C.; Loenen, E.J.; Hensen, J.L.M. Considerations on design optimization criteria for windows providing low energy consumption and high visual comfort. Appl. Energy
**2012**, 95, 238–245. [Google Scholar] [CrossRef] [Green Version] - Acosta, I.; Campano, M.A.; Molina, J.F. Window design in architecture: Analysis of energy savings for lighting and visual comfort in residential spaces. Appl. Energy
**2016**, 168, 493–506. [Google Scholar] [CrossRef] - Soori, P.K.; Vishwas, M. Lighting control strategy for energy efficient office lighting system design. Energy Build.
**2013**, 66, 329–337. [Google Scholar] [CrossRef] - Choi, H.; Hong, S.; Choi, A.; Sung, M. Toward the accuracy of prediction for energy savings potential and system performance using the daylight responsive dimming system. Energy Build.
**2016**, 133, 271–280. [Google Scholar] [CrossRef] - Roisin, B.; Bodart, M.; Deneyer, A.; D’Herdt, P. Lighting energy savings in offices using different control systems and their real consumption. Energy Build.
**2008**, 40, 514–523. [Google Scholar] [CrossRef] - Shishegar, N.; Boubekri, M. Quantifying electrical energy savings in offices through installing daylight responsive control systems in hot climates. Energy Build.
**2017**, 153, 87–98. [Google Scholar] [CrossRef] - Acosta, I.; Campano, M.A.; Bustamante, P.; Molina, J.F. Smart Controls for Lighting Design: Towards a Study of the Boundary Conditions. Int. J. Eng. Technol.
**2018**, 10, 481–486. [Google Scholar] [CrossRef] - Li, D.H.W.; Cheung, K.L.; Wong, S.L.; Lam, T.N.T. An analysis of energy-efficient light fittings and lighting controls. Appl. Energy
**2010**, 87, 558–567. [Google Scholar] [CrossRef] - Williams, A.; Atkinson, B.; Garbesi, K.; Page, E.; Rubinstein, F. Lighting controls in commercial buildings. Leukos
**2012**, 8, 61–180. [Google Scholar] - Xu, L.; Pan, Y.; Yao, Y.; Cai, D.; Huang, Z.; Linder, N. Lighting energy efficiency in offices under different control strategies. Energy Build.
**2017**, 138, 127–139. [Google Scholar] [CrossRef] - Bellia, L.; Fragliasso, F.; Stefanizzi, E. Why are daylight-linked controls (DLCs) not so spread? A literatura review. Energy Build.
**2016**, 106, 301–312. [Google Scholar] [CrossRef] - Gunay, H.B.; O’Brien, W.; Beausoleil-Morrison, I.; Huchuk, B. On adaptive occupant-learning window blind and lighting controls. Build. Res. Inf.
**2014**, 42, 739–756. [Google Scholar] [CrossRef] - Haldi, F.; Robinson, D. The impact of occupants’ behaviour on building energy demand. J. Build. Perform. Simul.
**2011**, 4, 323–338. [Google Scholar] [CrossRef] - Mardaljevic, J.; Heschong, L.; Lee, E. Daylight metrics and energy savings. Light. Res. Technol.
**2009**, 41, 261–283. [Google Scholar] [CrossRef] [Green Version] - Yu, X.; Su, Y. Daylight availability assessment and its potential energy saving estimation—A literature review. Renew. Sustain. Energy Rev.
**2015**, 52, 494–503. [Google Scholar] [CrossRef] - Xue, P.; Mak, C.M.; Huang, Y. Quantification of luminous comfort with dynamic daylight metrics in residential buildings. Energy Build.
**2016**, 117, 99–108. [Google Scholar] [CrossRef] - Lawrence Berkley National Laboratory. EnergyPlus Engineering Reference. The Reference to EnergyPlus Calculations; Technical Report; Lawrence Berkeley National Laboratory: Berkeley, CA, USA, 2012; p. 1278.
- Perez, R.; Seals, R.; Michalsky, J. All-Weather Model for Sky Luminance Distribution—Preliminary Configuration and Validation. Sol. Energy
**1993**, 50, 235–245. [Google Scholar] [CrossRef] - Commission Internationale de l’Éclairage (CIE). Spatial Distribution of Daylight—CIE Standard General Sky; CIE S 011/E: 2003; Commission Internationale de l’Éclairage: Vienna, Austria, 2003. [Google Scholar]
- ASHRAE International Weather for Energy Calculations. 2001. Available online: https://www.ashrae.org/technical-resources/bookstore/ashrae-international-weather-files-for-energy-calculations-2-0-iwec2 (accessed on 5 February 2018).
- De la Flor, F.J.S.; Dominguez, S.A.; Félix, J.L.M.; Falcón, R.G. Climatic zoning and its application to Spanish building energy performance regulations. Energy Build.
**2008**, 40, 1984–1990. [Google Scholar] [CrossRef] - Munoz, C.M.; Esquivias, P.M.; Rangel, D.; Acosta, I.; Navarro, J. Climate-based daylighting analysis for the effects of location, orientation and obstruction. Light. Res. Technol.
**2014**, 46, 268–280. [Google Scholar] [CrossRef] - Shahzad, S.; Brennan, J.; Theodossopoulos, D.; Hughes, B.K.; Calautit, J.K. Energy and comfort in contemporary open plan and traditional personal offices. Appl. Energy
**2017**, 185, 1542–1555. [Google Scholar] [CrossRef] - Bodart, M.; de Herde, A. Global energy savings in offices buildings by the use of daylighting. Energy Build.
**2002**, 34, 421–429. [Google Scholar] [CrossRef] - Dubois, M.C.; Blomsterberg, Å. Energy saving potential and strategies for electric lighting in future North European, low energy office buildings: A literature review. Energy Build.
**2011**, 43, 2572–2582. [Google Scholar] [CrossRef] - AEN/CTN 72. Light and Lighting—Lighting of Work Places—Part 1: Indoor Work Places 2012. UNE-EN 12464-1:2012. Available online: https://www.cibse.org/getmedia/3b3cba92-f3cc-4477-bc63-8c02fc31472c/EN12464-2011.pdf.aspx (accessed on 10 November 2018).
- Acosta, I.; Munoz, C.M.; Esquivias, P.M.; Rangel, D.; Navarro, J. Analysis of the accuracy of the sky component calculation in daylighting simulation programs. Sol. Energy
**2015**, 119, 54–67. [Google Scholar] [CrossRef] - Seo, D.; Park, L.; Ihm, P.; Krarti, M. Optimal electrical circuiting layout and desk location for daylighting controlled spaces. Energy Build.
**2012**, 51, 122–130. [Google Scholar] [CrossRef] - Tzempelikos, A. The impact of manual light switching on lighting energy consumption for a typical office building. In Proceedings of the International High Performance Buildings Conference, 2010; Volume 3384, pp. 1–8. Available online: https://docs.lib.purdue.edu/ihpbc/32 (accessed on 23 September 2018).
- Bellia, L.; Fragliasso, F. New parameters to evaluate the capability of a daylight-linked control system in complementing daylight. Energy Build.
**2017**, 123, 223–242. [Google Scholar] [CrossRef] - Bellia, L.; Fragliasso, F.; Riccio, G. Daylight fluctuations effect on the functioning of different daylight-linked control systems. Energy Build.
**2018**, 135, 162–193. [Google Scholar] [CrossRef] - Mardaljevic, J. Validation of a lighting simulation program under real sky conditions. Light. Res. Technol.
**1995**, 27, 181–188. [Google Scholar] [CrossRef] - Acosta, I.; Navarro, J.; Sendra, J.J. Towards an Analysis of Daylighting Simulation Software. Energies
**2011**, 4, 1010–1024. [Google Scholar] [CrossRef] [Green Version] - Reinhart, C.F.; Walkenhorst, O. Validation of dynamic RADIANCE-based daylight simulations for a test office with external blinds. Energy Build.
**2001**, 33, 683–697. [Google Scholar] [CrossRef] - Reinhart, C.F.; Breton, P.F. Experimental validation of Autodesk (R) 3Ds Max (R) Design 2009 and Daysim 3.0. Leukos
**2009**, 6, 7–35. [Google Scholar] - Commission Internationale de l’Éclairage (CIE). Test Cases to Assess the Accuracy of Lighting Computer Programs; CIE 171:2006; Commission Internationale de l’Éclairage: Vienna, Austria, 2006. [Google Scholar]
- Association Suisse des Electriciens. Éclairage intérieur par la lumière du jour, Association Suisse Des Electriciens; Swiss Norm SN 418911; Association Suisse des Electriciens: Zurich, Switzerland, 1989. [Google Scholar]
- Reinhart, C.F.; Mardaljevic, J.; Rogers, Z. Dynamic Daylight Performance Metrics for Sustainable Building Design. Leukos
**2006**, 3, 7–31. [Google Scholar] - Galatioto, A.; Beccali, M. Aspects and issues of daylighting assessment: A review study. Renew. Sustain. Energy Rev.
**2016**, 66, 852–860. [Google Scholar] [CrossRef] - Aguer, M.; Jutglar, L.; Miranda, A.L. El Ahorro Energético: Estudios de Viabilidad Económica; Ediciones Díaz de Santos: Madrid, Spain, 2006. [Google Scholar]
- Pombo, O.; Allacker, K.; Rivela, B.; Neila, J. Sustainability assessment of energy saving measures: A multi-criteria approach for residential building retrofitting a Case study of the Spanish housing stock. Energy Build.
**2016**, 116, 384–394. [Google Scholar] [CrossRef] [Green Version] - Santamaría, J.; Girón, S.; Campano, M.A. Economic assessments of passive thermal rehabilitations of dwellings in Mediterranean climate. Energy Build.
**2016**, 128, 772–784. [Google Scholar] [CrossRef] - EUROSTAT. Electricity Prices for Domestic Consumers. Available online: http://ec.europa.eu/eurostat/tgm/table.do?tab=table&init=1&plugin=1&language=en&pcode=ten00117 (accessed on 7 December 2016).
- Campano, M.A.; Acosta, I.; León, A.L.; Calama, C. Validation Study for Daylight Dynamic Metrics by Using Test Cells in Mediterranean Area. Int. J. Eng. Technol.
**2018**, 10, 487–491. [Google Scholar] [CrossRef] - León, A.L.; Suárez, R.; Bustamante, P.; Campano, M.A.; Moreno, D. Design and Performance of Test Cells as an Energy Evaluation Model of Facades in a Mediterranean Building Area. Energies
**2017**, 10, 1816. [Google Scholar] [CrossRef]

**Figure 3.**(

**a**) Inner view of the test cell with sensor distribution, (

**b**) virtual model with illuminance study points.

**Figure 4.**Dynamic daylight metrics and average power consumption according to different smart controls for room models located in Stockholm.

**Figure 5.**Daylight dynamic metrics and average power consumption according to different smart controls for room models located in London.

**Figure 6.**Dynamic daylight performance metrics and average power consumption according to different smart controls for room models located in Madrid.

Model | Depth | Window to Façade | Visible Light Trans-mittance | Joinery Reflectance | Ceiling Reflectance | Wall Reflectance | Floor Reflectance | Locations | ||
---|---|---|---|---|---|---|---|---|---|---|

330B | 3 m | 30% | 0.7 | 0.9 | 0.8 | 0.6 | 0.4 | Stockholm (S) | London (L) | Madrid (M) |

360B | 3 m | 60% | 0.7 | 0.9 | 0.8 | 0.6 | 0.4 | Stockholm (S) | London (L) | Madrid (M) |

390B | 3 m | 90% | 0.7 | 0.9 | 0.8 | 0.6 | 0.4 | Stockholm (S) | London (L) | Madrid (M) |

330D | 3 m | 30% | 0.7 | 0.9 | 0.6 | 0.4 | 0.2 | Stockholm (S) | London (L) | Madrid (M) |

360D | 3 m | 60% | 0.7 | 0.9 | 0.6 | 0.4 | 0.2 | Stockholm (S) | London (L) | Madrid (M) |

390D | 3 m | 90% | 0.7 | 0.9 | 0.6 | 0.4 | 0.2 | Stockholm (S) | London (L) | Madrid (M) |

630B | 6 m | 30% | 0.7 | 0.9 | 0.8 | 0.6 | 0.4 | Stockholm (S) | London (L) | Madrid (M) |

660B | 6 m | 60% | 0.7 | 0.9 | 0.8 | 0.6 | 0.4 | Stockholm (S) | London (L) | Madrid (M) |

690B | 6 m | 90% | 0.7 | 0.9 | 0.8 | 0.6 | 0.4 | Stockholm (S) | London (L) | Madrid (M) |

630D | 6 m | 30% | 0.7 | 0.9 | 0.6 | 0.4 | 0.2 | Stockholm (S) | London (L) | Madrid (M) |

660D | 6 m | 60% | 0.7 | 0.9 | 0.6 | 0.4 | 0.2 | Stockholm (S) | London (L) | Madrid (M) |

690D | 6 m | 90% | 0.7 | 0.9 | 0.6 | 0.4 | 0.2 | Stockholm (S) | London (L) | Madrid (M) |

930B | 9 m | 30% | 0.7 | 0.9 | 0.8 | 0.6 | 0.4 | Stockholm (S) | London (L) | Madrid (M) |

960B | 9 m | 60% | 0.7 | 0.9 | 0.8 | 0.6 | 0.4 | Stockholm (S) | London (L) | Madrid (M) |

990B | 9 m | 90% | 0.7 | 0.9 | 0.8 | 0.6 | 0.4 | Stockholm (S) | London (L) | Madrid (M) |

930D | 9 m | 30% | 0.7 | 0.9 | 0.6 | 0.4 | 0.2 | Stockholm (S) | London (L) | Madrid (M) |

960D | 9 m | 60% | 0.7 | 0.9 | 0.6 | 0.4 | 0.2 | Stockholm (S) | London (L) | Madrid (M) |

990D | 9 m | 90% | 0.7 | 0.9 | 0.6 | 0.4 | 0.2 | Stockholm (S) | London (L) | Madrid (M) |

CASE 1: ON/OFF LIGHTING WITH SEPARATE ROWS FAÇADE-BACK | |||||||

MATERIAL | Cost per unit | Units | Total cost | ||||

Stockholm | London | Madrid | Stockholm | London | Madrid | ||

Electric cable, single-pole, section 1.5 mm^{2}, crosslinked polyethylene insulation. | 0.46 €/m | 0.46 €/m | 0.46 €/m | 3.20 m | 1.47 € | 1.47 € | 1.47 € |

Single-pole switch, medium range, rated voltage 250 V, according to EN 60669. | 13.90 €/U | 13.90 €/U | 13.90 €/U | 1.00 U | 13.90 € | 13.90 € | 13.90 € |

Labor costs of electrical technician. | 39.00 €/h | 26.40 €/h | 20.60 €/h | 1.50 h | 58.50 € | 39.60 € | 30.90 € |

INITIAL INVESTMENT COSTS | 73.87 € | 54.97 € | 46.27 € | ||||

CASE 2: DIMMING ALL LIGHTING | |||||||

MATERIAL | Cost per unit | Units | Total cost | ||||

Stockholm | London | Madrid | Stockholm | London | Madrid | ||

Arduino Uno Rev 3 chip Atmega328 for control system, including timer, servo and connections for pulse-width modulation (PWM) control. | 35.00 €/U | 35.00 €/U | 35.00 €/U | 1.00 U | 35.00 € | 35.00 € | 35.00 € |

Electric transformer from 220/120 V to 10 V, including connections. | 8.00 €/U | 8.00 €/U | 8.00 €/U | 1.00 U | 8.00 € | 8.00 € | 8.00 € |

Mounting box of high-density polyethylene, including connections. | 12.00 €/U | 12.00 €/U | 12.00 €/U | 1.00 U | 12.00 € | 12.00 € | 12.00 € |

Lux-meter Adafruit TSL2561 Digital, spectral response according to standard photopic vision. | 16.00 €/U | 16.00 €/U | 16.00 €/U | 1.00 U | 16.00 € | 16.00 € | 16.00 € |

Labor costs of electrical technician. | 39.00 €/h | 26.40 €/h | 20.60 €/h | 2.50 h | 97.50 € | 66.00 € | 51.50 € |

INITIAL INVESTMENT COSTS | 168.50 € | 137.00 € | 122.50 € | ||||

CASE 3: DIMMING LIGHTING WITH SEPARATE ROWS FAÇADE-BACK | |||||||

MATERIAL | Cost per unit | Units | Total cost | ||||

Stockholm | London | Madrid | Stockholm | London | Madrid | ||

Electric cable, single-pole, section 1.5 mm^{2}, crosslinked polyethylene insulation. | 0.46 €/m | 0.46 €/m | 0.46 €/m | 3.20 m | 1.47 € | 1.47 € | 1.47 € |

Single-pole switch, medium range, rated voltage 250 V, according to EN 60669. | 13.90 €/U | 13.90 €/U | 13.90 €/U | 2.00 U | 27.80 € | 27.80 € | 27.80 € |

Arduino Uno Rev 3 chip Atmega328 for control system, including timer, servo and connections for PWM control. | 35.00 €/U | 35.00 €/U | 35.00 €/U | 2.00 U | 70.00 € | 70.00 € | 70.00 € |

Electric transformer from 220/120 V to 10 V, including connections. | 8.00 €/U | 8.00 €/U | 8.00 €/U | 2.00 U | 16.00 € | 16.00 € | 16.00 € |

Mounting box of high-density polyethylene, including connections. | 12.00 €/U | 12.00 €/U | 12.00 €/U | 2.00 U | 24.00 € | 24.00 € | 24.00 € |

Lux-meter Adafruit TSL2561 Digital, spectral response according to standard photopic vision. | 16.00 €/U | 16.00 €/U | 16.00 €/U | 2.00 U | 32.00 € | 32.00 € | 32.00 € |

Labor costs of electrical technician. | 39.00 €/h | 26.40 €/h | 20.60 €/h | 3.50 h | 136.50 € | 92.40 € | 72.10 € |

INITIAL INVESTMENT COSTS | 307.77 € | 263.67 € | 243.37 € |

Ambient Bounces | 7 |

Ambient Divisions | 1500 |

Ambient Super-samples | 100 |

Ambient Resolution | 300 |

Ambient Accuracy | 0.05 |

Limit Reflection | 10 |

Specular Threshold | 0.0000 |

Specular Jitter | 1.0000 |

Limit Weight | 0.0040 |

Direct Jitter | 0.0000 |

Direct Sampling | 0.2000 |

Direct Relays | 2 |

Direct Pretest Density | 512 |

Sweden (Stockholm) | United Kingdom (London) | Spain (Madrid) | |
---|---|---|---|

Annual electric energy cost in 2016 (EC_{2016}) | 0.1894 €/(kW·h) | 0.1951 €/(kW·h) | 0.2185 €/(kW·h) |

Annual Growth Rate 2005–2016 (AGR_{E}) | 2.8% | 7.5% | 6.5% |

**Table 5.**DA and DAC values obtained for test cell illuminance measurements and for model simulation calculations.

MEASUREMENTS | ||||||||||||||||

Daylight Autonomy (DA) | Continuous Daylight Autonomy (DAC) | |||||||||||||||

0.2 m | 0.6 m | 1.0 m | 1.4 m | 1.8 m | 2.2 m | 2.6 m | 3.0 m | 0.2 m | 0.6 m | 1.0 m | 1.4 m | 1.8 m | 2.2 m | 2.6 m | 3.0 m | |

100 lx | 83% | 90% | 91% | 91% | 89% | 88% | 87% | 86% | 90% | 95% | 95% | 95% | 94% | 94% | 92% | 92% |

250 lx | 68% | 84% | 85% | 84% | 80% | 76% | 74% | 73% | 81% | 90% | 91% | 90% | 89% | 88% | 85% | 84% |

500 lx | 53% | 72% | 74% | 72% | 67% | 63% | 54% | 45% | 71% | 84% | 84% | 83% | 81% | 79% | 74% | 73% |

SIMULATION | ||||||||||||||||

Daylight Autonomy (DA) | Continuous Daylight Autonomy (DAC) | |||||||||||||||

0.2 m | 0.6 m | 1.0 m | 1.4 m | 1.8 m | 2.2 m | 2.6 m | 3.0 m | 0.2 m | 0.6 m | 1.0 m | 1.4 m | 1.8 m | 2.2 m | 2.6 m | 3.0 m | |

100 lx | 85% | 89% | 89% | 89% | 88% | 88% | 87% | 86% | 89% | 91% | 91% | 91% | 91% | 90% | 90% | 89% |

250 lx | 74% | 83% | 84% | 83% | 82% | 81% | 78% | 77% | 83% | 88% | 88% | 88% | 87% | 87% | 86% | 85% |

500 lx | 56% | 74% | 75% | 73% | 69% | 64% | 56% | 49% | 74% | 83% | 84% | 83% | 81% | 80% | 77% | 75% |

DIVERGENCE MEASUREMENT-SIMULATION | ||||||||||||||||

Daylight Autonomy (DA) | Continuous Daylight Autonomy (DAC) | |||||||||||||||

0.2 m | 0.6 m | 1.0 m | 1.4 m | 1.8 m | 2.2 m | 2.6 m | 3.0 m | 0.2 m | 0.6 m | 1.0 m | 1.4 m | 1.8 m | 2.2 m | 2.6 m | 3.0 m | |

100 lx | 2.0% | −1.6% | −2.7% | −2.0% | −1.5% | −0.4% | 0.1% | −0.3% | −1.0% | −4.2% | −4.2% | −4.0% | −3.2% | −3.9% | −2.4% | −3.2% |

250 lx | 8.3% | −1.6% | −1.7% | −1.6% | 2.8% | 5.9% | 6.1% | 6.2% | 2.2% | −2.5% | −2.8% | −2.4% | −2.2% | −1.2% | 1.1% | 0.6% |

500 lx | 5.8% | 2.7% | 2.0% | 1.6% | 3.5% | 1.1% | 3.0% | 8.4% | 3.8% | −0.7% | −0.3% | −0.5% | −0.1% | 0.8% | 3.4% | 3.1% |

AVERAGE POWER CONSUMPTION (W/m^{2}) | ||||||
---|---|---|---|---|---|---|

Stockholm | ||||||

Depth | Window-to-Façade Ratio | Reflec-tance | Case Study 0 | Case Study 1 | Case Study 2 | Case Study 3 |

3.0 m | 30% | High | 3.3 | 3.3 | 2.2 | 2.2 |

3.0 m | 60% | High | 2.3 | 2.3 | 1.6 | 1.6 |

3.0 m | 90% | High | 1.9 | 1.9 | 1.4 | 1.4 |

3.0 m | 30% | Low | 4.9 | 4.9 | 3.1 | 3.1 |

3.0 m | 60% | Low | 3.4 | 3.4 | 2.2 | 2.2 |

3.0 m | 90% | Low | 2.8 | 2.8 | 1.9 | 1.9 |

6.0 m | 30% | High | 7.1 | 5.7 | 4.0 | 3.4 |

6.0 m | 60% | High | 4.1 | 3.6 | 2.7 | 2.3 |

6.0 m | 90% | High | 3.3 | 2.9 | 2.2 | 1.9 |

6.0 m | 30% | Low | 9.7 | 8.2 | 6.8 | 5.4 |

6.0 m | 60% | Low | 7.4 | 5.8 | 4.4 | 3.5 |

6.0 m | 90% | Low | 5.5 | 4.5 | 3.5 | 2.9 |

9.0 m | 30% | High | 8.1 | 6.9 | 6.3 | 5.2 |

9.0 m | 60% | High | 7.4 | 6.0 | 4.2 | 3.5 |

9.0 m | 90% | High | 5.2 | 4.3 | 3.2 | 2.7 |

9.0 m | 30% | Low | 9.7 | 8.6 | 8.5 | 7.0 |

9.0 m | 60% | Low | 9.7 | 7.9 | 7.3 | 5.8 |

9.0 m | 90% | Low | 9.7 | 7.6 | 6.1 | 4.9 |

ANNUAL ENERGY SAVING (kWh) | |||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|

Stockholm | |||||||||||

Width | 12.0 m | 8.0 m | 4.0 m | 12.0 m | 8.0 m | 4.0 m | 12.0 m | 8.0 m | 4.0 m | ||

Depth | Window-to-Façade Ratio | Reflec-tance | Case Study 3: Dimming Control with Two Separate Rows | Case Study 2: Dimming Control for All Luminaires | Case Study 1: On/Off Control with Two Separate Rows | ||||||

3.0 m | 30% | High | - | - | - | 106 | 71 | 35 | - | - | - |

3.0 m | 60% | High | - | - | - | 68 | 45 | 23 | - | - | - |

3.0 m | 90% | High | - | - | - | 53 | 35 | 18 | - | - | - |

3.0 m | 30% | Low | - | - | - | 164 | 109 | 55 | - | - | - |

3.0 m | 60% | Low | - | - | - | 109 | 73 | 36 | - | - | - |

3.0 m | 90% | Low | - | - | - | 82 | 55 | 27 | - | - | - |

6.0 m | 30% | High | 697 | 465 | 232 | 576 | 384 | 192 | 258 | 172 | 86 |

6.0 m | 60% | High | 333 | 222 | 111 | 273 | 182 | 91 | 98 | 66 | 33 |

6.0 m | 90% | High | 258 | 172 | 86 | 212 | 141 | 71 | 83 | 56 | 28 |

6.0 m | 30% | Low | 809 | 539 | 270 | 545 | 364 | 182 | 282 | 188 | 94 |

6.0 m | 60% | Low | 718 | 479 | 239 | 564 | 376 | 188 | 291 | 194 | 97 |

6.0 m | 90% | Low | 500 | 333 | 167 | 382 | 255 | 127 | 191 | 127 | 64 |

9.0 m | 30% | High | 826 | 551 | 275 | 500 | 333 | 167 | 341 | 227 | 114 |

9.0 m | 60% | High | 1091 | 727 | 364 | 886 | 591 | 295 | 394 | 263 | 131 |

9.0 m | 90% | High | 689 | 460 | 230 | 545 | 364 | 182 | 250 | 167 | 83 |

9.0 m | 30% | Low | 764 | 509 | 255 | 327 | 218 | 109 | 300 | 200 | 100 |

9.0 m | 60% | Low | 1100 | 733 | 367 | 682 | 455 | 227 | 509 | 339 | 170 |

9.0 m | 90% | Low | 1364 | 909 | 455 | 1009 | 673 | 336 | 582 | 388 | 194 |

AVERAGE POWER CONSUMPTION (W/m^{2}) | ||||||
---|---|---|---|---|---|---|

London | ||||||

Depth | Window-to-Façade Ratio | Reflec-tance | Case Study 0 | Case Study 1 | Case Study 2 | Case Study 3 |

3.0 m | 30% | High | 3.8 | 3.8 | 2.5 | 2.5 |

3.0 m | 60% | High | 2.8 | 2.8 | 1.9 | 1.9 |

3.0 m | 90% | High | 2.3 | 2.3 | 1.5 | 1.5 |

3.0 m | 30% | Low | 5.6 | 5.6 | 3.6 | 3.6 |

3.0 m | 60% | Low | 4.0 | 4.0 | 2.6 | 2.6 |

3.0 m | 90% | Low | 3.3 | 3.3 | 2.2 | 2.2 |

6.0 m | 30% | High | 7.8 | 6.4 | 4.8 | 4.0 |

6.0 m | 60% | High | 4.9 | 4.2 | 3.1 | 2.7 |

6.0 m | 90% | High | 3.9 | 3.4 | 2.5 | 2.2 |

6.0 m | 30% | Low | 9.7 | 8.9 | 7.3 | 6.0 |

6.0 m | 60% | Low | 8.7 | 6.9 | 5.1 | 4.2 |

6.0 m | 90% | Low | 6.4 | 5.2 | 4.0 | 3.3 |

9.0 m | 30% | High | 8.1 | 7.1 | 6.7 | 5.6 |

9.0 m | 60% | High | 7.9 | 6.5 | 4.9 | 4.0 |

9.0 m | 90% | High | 6.4 | 5.3 | 3.8 | 3.2 |

9.0 m | 30% | Low | 9.7 | 9.1 | 8.7 | 7.3 |

9.0 m | 60% | Low | 9.7 | 8.2 | 7.7 | 6.2 |

9.0 m | 90% | Low | 9.7 | 7.9 | 6.8 | 5.4 |

ANNUAL ENERGY SAVING (kWh) | |||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|

London | |||||||||||

Width | 12.0 m | 8.0 m | 4.0 m | 12.0 m | 8.0 m | 4.0 m | 12.0 m | 8.0 m | 4.0 m | ||

Depth | Window-to-Façade Ratio | Reflec-tance | Case Study 3: Dimming Control with Two Separate Rows | Case Study 2: Dimming Control for All Luminaires | Case Study 1: On/Off Control with Two Separate Rows | ||||||

3.0 m | 30% | High | - | - | - | 121 | 81 | 40 | - | - | - |

3.0 m | 60% | High | - | - | - | 83 | 56 | 28 | - | - | - |

3.0 m | 90% | High | - | - | - | 68 | 45 | 23 | - | - | - |

3.0 m | 30% | Low | - | - | - | 191 | 127 | 64 | - | - | - |

3.0 m | 60% | Low | - | - | - | 127 | 85 | 42 | - | - | - |

3.0 m | 90% | Low | - | - | - | 100 | 67 | 33 | - | - | - |

6.0 m | 30% | High | 705 | 470 | 235 | 561 | 374 | 187 | 250 | 167 | 83 |

6.0 m | 60% | High | 409 | 273 | 136 | 333 | 222 | 111 | 121 | 81 | 40 |

6.0 m | 90% | High | 311 | 207 | 104 | 258 | 172 | 86 | 98 | 66 | 33 |

6.0 m | 30% | Low | 700 | 467 | 233 | 455 | 303 | 152 | 155 | 103 | 52 |

6.0 m | 60% | Low | 855 | 570 | 285 | 673 | 448 | 224 | 345 | 230 | 115 |

6.0 m | 90% | Low | 582 | 388 | 194 | 455 | 303 | 152 | 218 | 145 | 73 |

9.0 m | 30% | High | 705 | 470 | 235 | 386 | 258 | 129 | 265 | 177 | 88 |

9.0 m | 60% | High | 1076 | 717 | 359 | 841 | 561 | 280 | 386 | 258 | 129 |

9.0 m | 90% | High | 902 | 601 | 301 | 727 | 485 | 242 | 318 | 212 | 106 |

9.0 m | 30% | Low | 664 | 442 | 221 | 273 | 182 | 91 | 173 | 115 | 58 |

9.0 m | 60% | Low | 991 | 661 | 330 | 573 | 382 | 191 | 427 | 285 | 142 |

9.0 m | 90% | Low | 1209 | 806 | 403 | 818 | 545 | 273 | 518 | 345 | 173 |

AVERAGE POWER CONSUMPTION (W/m^{2}) | ||||||
---|---|---|---|---|---|---|

Madrid | ||||||

Depth | Window-to-Façade Ratio | Reflec-tance | Case Study 0 | Case Study 1 | Case Study 2 | Case Study 3 |

3.0 m | 30% | High | 1.7 | 1.7 | 1.1 | 1.1 |

3.0 m | 60% | High | 1.1 | 1.1 | 0.7 | 0.7 |

3.0 m | 90% | High | 0.9 | 0.9 | 0.6 | 0.6 |

3.0 m | 30% | Low | 3.0 | 3.0 | 1.7 | 1.7 |

3.0 m | 60% | Low | 1.7 | 1.7 | 1.1 | 1.1 |

3.0 m | 90% | Low | 1.3 | 1.3 | 1.0 | 1.0 |

6.0 m | 30% | High | 6.1 | 4.5 | 2.7 | 2.1 |

6.0 m | 60% | High | 2.3 | 1.9 | 1.3 | 1.1 |

6.0 m | 90% | High | 1.6 | 1.4 | 1.0 | 0.9 |

6.0 m | 30% | Low | 9.7 | 7.7 | 5.7 | 4.1 |

6.0 m | 60% | Low | 6.1 | 4.3 | 2.7 | 2.0 |

6.0 m | 90% | Low | 3.6 | 2.7 | 1.8 | 1.5 |

9.0 m | 30% | High | 8.1 | 6.4 | 5.7 | 4.3 |

9.0 m | 60% | High | 6.4 | 4.8 | 2.8 | 2.2 |

9.0 m | 90% | High | 3.8 | 2.9 | 1.9 | 1.5 |

9.0 m | 30% | Low | 9.7 | 8.4 | 8.2 | 6.2 |

9.0 m | 60% | Low | 9.7 | 7.3 | 6.3 | 4.7 |

9.0 m | 90% | Low | 9.7 | 7.1 | 4.8 | 3.6 |

ANNUAL ENERGY SAVING (kWh) | |||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|

Madrid | |||||||||||

Width | 12.0 m | 8.0 m | 4.0 m | 12.0 m | 8.0 m | 4.0 m | 12.0 m | 8.0 m | 4.0 m | ||

Depth | Window-to-Façade Ratio | Reflec-tance | Case Study 3: Dimming Control with Two Separate Rows | Case Study 2: Dimming Control for All Luminaires | Case Study 1: On/Off Control with Two Separate Rows | ||||||

3.0 m | 30% | High | - | - | - | 61 | 40 | 20 | - | - | - |

3.0 m | 60% | High | - | - | - | 30 | 20 | 10 | - | - | - |

3.0 m | 90% | High | - | - | - | 23 | 15 | 8 | - | - | - |

3.0 m | 30% | Low | - | - | - | 127 | 85 | 42 | - | - | - |

3.0 m | 60% | Low | - | - | - | 55 | 36 | 18 | - | - | - |

3.0 m | 90% | Low | - | - | - | 27 | 18 | 9 | - | - | - |

6.0 m | 30% | High | 750 | 500 | 250 | 636 | 424 | 212 | 303 | 202 | 101 |

6.0 m | 60% | High | 227 | 152 | 76 | 197 | 131 | 66 | 76 | 51 | 25 |

6.0 m | 90% | High | 136 | 91 | 45 | 121 | 81 | 40 | 45 | 30 | 15 |

6.0 m | 30% | Low | 1045 | 697 | 348 | 745 | 497 | 248 | 373 | 248 | 124 |

6.0 m | 60% | Low | 764 | 509 | 255 | 636 | 424 | 212 | 345 | 230 | 115 |

6.0 m | 90% | Low | 400 | 267 | 133 | 327 | 218 | 109 | 173 | 115 | 58 |

9.0 m | 30% | High | 1068 | 712 | 356 | 682 | 455 | 227 | 477 | 318 | 159 |

9.0 m | 60% | High | 1174 | 783 | 391 | 1000 | 667 | 333 | 447 | 298 | 149 |

9.0 m | 90% | High | 644 | 429 | 215 | 545 | 364 | 182 | 242 | 162 | 81 |

9.0 m | 30% | Low | 973 | 648 | 324 | 436 | 291 | 145 | 382 | 255 | 127 |

9.0 m | 60% | Low | 1409 | 939 | 470 | 955 | 636 | 318 | 673 | 448 | 224 |

9.0 m | 90% | Low | 1727 | 1152 | 576 | 1391 | 927 | 464 | 745 | 497 | 248 |

PAYBACK PERIOD | |||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|

Stockholm | |||||||||||

Width | 12.0 m | 8.0 m | 4.0 m | 12.0 m | 8.0 m | 4.0 m | 12.0 m | 8.0 m | 4.0 m | ||

Depth | Window-to-Façade Ratio | Reflec-tance | Case Study 3: Dimming Control with Two Separate Rows | Case Study 2: Dimming Control for all Luminaires | Case Study 1: On/Off Control with Two Separate Rows | ||||||

3.0 m | 30% | High | - | - | - | 9 years | 13 years | 24 years | - | - | - |

3.0 m | 60% | High | - | - | - | 13 years | 19 years | 36 years | - | - | - |

3.0 m | 90% | High | - | - | - | 17 years | 24 years | 45 years | - | - | - |

3.0 m | 30% | Low | - | - | - | 6 years | 9 years | 16 years | - | - | - |

3.0 m | 60% | Low | - | - | - | 9 years | 13 years | 24 years | - | - | - |

3.0 m | 90% | Low | - | - | - | 11 years | 16 years | 31 years | - | - | - |

6.0 m | 30% | High | 3 years | 4 years | 7 years | 2 years | 3 years | 5 years | 2 years | 3 years | 5 years |

6.0 m | 60% | High | 5 years | 8 years | 15 years | 4 years | 5 years | 10 years | 5 years | 6 years | 12 years |

6.0 m | 90% | High | 7 years | 10 years | 19 years | 5 years | 7 years | 13 years | 5 years | 8 years | 14 years |

6.0 m | 30% | Low | 3 years | 4 years | 7 years | 2 years | 3 years | 5 years | 2 years | 3 years | 5 years |

6.0 m | 60% | Low | 3 years | 4 years | 7 years | 2 years | 3 years | 5 years | 2 years | 3 years | 5 years |

6.0 m | 90% | Low | 4 years | 5 years | 10 years | 3 years | 4 years | 7 years | 3 years | 4 years | 7 years |

9.0 m | 30% | High | 3 years | 3 years | 6 years | 2 years | 3 years | 6 years | 2 years | 2 years | 4 years |

9.0 m | 60% | High | 2 years | 3 years | 5 years | 2 years | 2 years | 4 years | 2 years | 2 years | 4 years |

9.0 m | 90% | High | 3 years | 4 years | 8 years | 2 years | 3 years | 5 years | 2 years | 3 years | 5 years |

9.0 m | 30% | Low | 3 years | 4 years | 7 years | 3 years | 5 years | 9 years | 2 years | 2 years | 4 years |

9.0 m | 60% | Low | 2 years | 3 years | 5 years | 2 years | 2 years | 4 years | 1 years | 2 years | 3 years |

9.0 m | 90% | Low | 2 years | 2 years | 4 years | 1 years | 2 years | 3 years | 1 years | 2 years | 3 years |

**Table 13.**Net present value in 10 years according to different lighting smart controls in Stockholm.

NET PRESENT VALUE IN 10 YEARS | |||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|

Stockholm | |||||||||||

Width | 12.0 m | 8.0 m | 4.0 m | 12.0 m | 8.0 m | 4.0 m | 12.0 m | 8.0 m | 4.0 m | ||

Depth | Window-to-Façade Ratio | Reflec-tance | Case Study 3: Dimming Control with Two Separate Rows | Case Study 2: Dimming Control for All Luminaires | Case Study 1: On/Off Control with Two Separate Rows | ||||||

3.0 m | 30% | High | - | - | - | 34 € | −33 € | −101 € | - | - | - |

3.0 m | 60% | High | - | - | - | −38 € | −82 € | −125 € | - | - | - |

3.0 m | 90% | High | - | - | - | −67 € | −101 € | −135 € | - | - | - |

3.0 m | 30% | Low | - | - | - | 145 € | 40 € | −64 € | - | - | - |

3.0 m | 60% | Low | - | - | - | 40 € | −29 € | −99 € | - | - | - |

3.0 m | 90% | Low | - | - | - | −12 € | −64 € | −116 € | - | - | - |

6.0 m | 30% | High | 1026 € | 581 € | 137 € | 933 € | 566 € | 199 € | 419 € | 255 € | 90 € |

6.0 m | 60% | High | 330 € | 117 € | −95 € | 353 € | 179 € | 5 € | 115 € | 52 € | −11 € |

6.0 m | 90% | High | 185 € | 21 € | −143 € | 237 € | 102 € | −33 € | 86 € | 32 € | −21 € |

6.0 m | 30% | Low | 1240 € | 724 € | 208 € | 875 € | 527 € | 179 € | 465 € | 286 € | 106 € |

6.0 m | 60% | Low | 1066 € | 608 € | 150 € | 910 € | 550 € | 191 € | 483 € | 297 € | 112 € |

6.0 m | 90% | Low | 649 € | 330 € | 11 € | 562 € | 319 € | 75 € | 291 € | 170 € | 48 € |

9.0 m | 30% | High | 1272 € | 746 € | 219 € | 788 € | 469 € | 150 € | 578 € | 361 € | 144 € |

9.0 m | 60% | High | 1780 € | 1084 € | 388 € | 1527 € | 962 € | 397 € | 680 € | 429 € | 177 € |

9.0 m | 90% | High | 1011 € | 572 € | 132 € | 875 € | 527 € | 179 € | 404 € | 245 € | 86 € |

9.0 m | 30% | Low | 1153 € | 666 € | 179 € | 458 € | 249 € | 40 € | 500 € | 309 € | 117 € |

9.0 m | 60% | Low | 1797 € | 1095 € | 394 € | 1136 € | 701 € | 266 € | 900 € | 576 € | 251 € |

9.0 m | 90% | Low | 2301 € | 1432 € | 562 € | 1762 € | 1119 € | 475 € | 1039 € | 668 € | 297 € |

PAYBACK PERIOD | |||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|

London | |||||||||||

Width | 12.0 m | 8.0 m | 4.0 m | 12.0 m | 8.0 m | 4.0 m | 12.0 m | 8.0 m | 4.0 m | ||

Depth | Window-to-Façade Ratio | Reflec-tance | Case Study 3: Dimming Control with Two Separate Rows | Case Study 2: Dimming Control for All Luminaires | Case Study 1: On/Off Control with Two Separate Rows | ||||||

3.0 m | 30% | High | - | - | - | 6 years | 8 years | 13 years | - | - | - |

3.0 m | 60% | High | - | - | - | 8 years | 11 years | 17 years | - | - | - |

3.0 m | 90% | High | - | - | - | 9 years | 12 years | 20 years | - | - | - |

3.0 m | 30% | Low | - | - | - | 4 years | 6 years | 10 years | - | - | - |

3.0 m | 60% | Low | - | - | - | 6 years | 8 years | 13 years | - | - | - |

3.0 m | 90% | Low | - | - | - | 7 years | 9 years | 15 years | - | - | - |

6.0 m | 30% | High | 2 years | 3 years | 6 years | 2 years | 2 years | 4 years | 2 years | 2 years | 4 years |

6.0 m | 60% | High | 4 years | 5 years | 9 years | 3 years | 4 years | 6 years | 3 years | 4 years | 7 years |

6.0 m | 90% | High | 5 years | 6 years | 11 years | 3 years | 4 years | 8 years | 3 years | 5 years | 8 years |

6.0 m | 30% | Low | 2 years | 3 years | 6 years | 2 years | 3 years | 5 years | 2 years | 3 years | 6 years |

6.0 m | 60% | Low | 2 years | 3 years | 5 years | 2 years | 2 years | 4 years | 1 years | 2 years | 3 years |

6.0 m | 90% | Low | 3 years | 4 years | 7 years | 2 years | 3 years | 5 years | 2 years | 2 years | 4 years |

9.0 m | 30% | High | 2 years | 3 years | 6 years | 2 years | 3 years | 6 years | 2 years | 2 years | 4 years |

9.0 m | 60% | High | 2 years | 2 years | 4 years | 1 years | 2 years | 3 years | 1 years | 2 years | 3 years |

9.0 m | 90% | High | 2 years | 3 years | 5 years | 1 years | 2 years | 3 years | 1 years | 2 years | 3 years |

9.0 m | 30% | Low | 3 years | 3 years | 6 years | 3 years | 4 years | 7 years | 2 years | 3 years | 5 years |

9.0 m | 60% | Low | 2 years | 3 years | 4 years | 2 years | 2 years | 4 years | 1 years | 2 years | 2 years |

9.0 m | 90% | Low | 2 years | 2 years | 4 years | 1 years | 2 years | 3 years | 1 years | 1 years | 2 years |

NET PRESENT VALUE IN 10 YEARS | |||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|

London | |||||||||||

Width | 12.0 m | 8.0 m | 4.0 m | 12.0 m | 8.0 m | 4.0 m | 12.0 m | 8.0 m | 4.0 m | ||

Depth | Window-to-Façade Ratio | Reflec-tance | Case Study 3: Dimming Control with Two Separate Rows | Case Study 2: Dimming Control for All Luminaires | Case Study 1: On/Off Control with Two Separate Rows | ||||||

3.0 m | 30% | High | - | - | - | 158 € | 60 € | −39 € | - | - | - |

3.0 m | 60% | High | - | - | - | 66 € | −2 € | −69 € | - | - | - |

3.0 m | 90% | High | - | - | - | 29 € | −26 € | −82 € | - | - | - |

3.0 m | 30% | Low | - | - | - | 328 € | 173 € | 18 € | - | - | - |

3.0 m | 60% | Low | - | - | - | 173 € | 70 € | −34 € | - | - | - |

3.0 m | 90% | Low | - | - | - | 107 € | 25 € | −56 € | - | - | - |

6.0 m | 30% | High | 1453 € | 881 € | 309 € | 1229 € | 773 € | 318 € | 554 € | 351 € | 148 € |

6.0 m | 60% | High | 733 € | 401 € | 69 € | 675 € | 404 € | 134 € | 240 € | 142 € | 43 € |

6.0 m | 90% | High | 493 € | 241 € | −11 € | 490 € | 281 € | 72 € | 185 € | 105 € | 25 € |

6.0 m | 30% | Low | 1442 € | 873 € | 305 € | 970 € | 601 € | 232 € | 322 € | 196 € | 71 € |

6.0 m | 60% | Low | 1818 € | 1124 € | 431 € | 1502 € | 956 € | 409 € | 787 € | 506 € | 226 € |

6.0 m | 90% | Low | 1154 € | 682 € | 209 € | 970 € | 601 € | 232 € | 477 € | 299 € | 122 € |

9.0 m | 30% | High | 1453 € | 881 € | 309 € | 804 € | 490 € | 177 € | 591 € | 376 € | 160 € |

9.0 m | 60% | High | 2357 € | 1484 € | 610 € | 1912 € | 1229 € | 546 € | 886 € | 573 € | 259 € |

9.0 m | 90% | High | 1933 € | 1201 € | 469 € | 1635 € | 1044 € | 454 € | 720 € | 462 € | 203 € |

9.0 m | 30% | Low | 1353 € | 814 € | 276 € | 527 € | 306 € | 84 € | 366 € | 226 € | 85 € |

9.0 m | 60% | Low | 2151 € | 1346 € | 541 € | 1258 € | 793 € | 328 € | 986 € | 639 € | 292 € |

9.0 m | 90% | Low | 2682 € | 1700 € | 718 € | 1856 € | 1192 € | 527 € | 1207 € | 787 € | 366 € |

PAYBACK PERIOD | |||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|

Madrid | |||||||||||

Width | 12.0 m | 8.0 m | 4.0 m | 12.0 m | 8.0 m | 4.0 m | 12.0 m | 8.0 m | 4.0 m | ||

Depth | Window-to-Façade Ratio | Reflec-tance | Case Study 3: Dimming Control with Two Separate Rows | Case Study 2: Dimming Control for All Luminaires | Case Study 1: On/Off Control with Two Separate Rows | ||||||

3.0 m | 30% | High | - | - | - | 9 years | 12 years | 19 years | - | - | - |

3.0 m | 60% | High | - | - | - | 15 years | 19 years | 30 years | - | - | - |

3.0 m | 90% | High | - | - | - | 18 years | 23 years | 35 years | - | - | - |

3.0 m | 30% | Low | - | - | - | 5 years | 7 years | 11 years | - | - | - |

3.0 m | 60% | Low | - | - | - | 9 years | 13 years | 21 years | - | - | - |

3.0 m | 90% | Low | - | - | - | 16 years | 21 years | 32 years | - | - | - |

6.0 m | 30% | High | 2 years | 3 years | 5 years | 1 years | 2 years | 3 years | 1 years | 2 years | 3 years |

6.0 m | 60% | High | 5 years | 7 years | 12 years | 3 years | 5 years | 8 years | 3 years | 5 years | 8 years |

6.0 m | 90% | High | 8 years | 11 years | 18 years | 5 years | 7 years | 12 years | 5 years | 7 years | 12 years |

6.0 m | 30% | Low | 2 years | 2 years | 4 years | 1 years | 2 years | 3 years | 1 years | 1 years | 2 years |

6.0 m | 60% | Low | 2 years | 3 years | 5 years | 1 years | 2 years | 3 years | 1 years | 1 years | 2 years |

6.0 m | 90% | Low | 3 years | 4 years | 8 years | 2 years | 3 years | 5 years | 2 years | 2 years | 4 years |

9.0 m | 30% | High | 2 years | 2 years | 4 years | 1 years | 2 years | 3 years | 1 years | 1 years | 2 years |

9.0 m | 60% | High | 1 years | 2 years | 3 years | 1 years | 1 years | 2 years | 1 years | 1 years | 2 years |

9.0 m | 90% | High | 2 years | 3 years | 5 years | 2 years | 2 years | 4 years | 1 years | 2 years | 3 years |

9.0 m | 30% | Low | 2 years | 2 years | 4 years | 2 years | 2 years | 4 years | 1 years | 1 years | 2 years |

9.0 m | 60% | Low | 1 years | 2 years | 3 years | 1 years | 1 years | 2 years | 1 years | 1 years | 1 years |

9.0 m | 90% | Low | 1 years | 1 years | 2 years | 1 years | 1 years | 2 years | 1 years | 1 years | 1 years |

NET PRESENT VALUE IN 10 YEARS | |||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|

Madrid | |||||||||||

NPV | Width | 12.0 m | 8.0 m | 4.0 m | 12.0 m | 8.0 m | 4.0 m | 12.0 m | 8.0 m | 4.0 m | |

Depth | Window-to-Façade Ratio | Reflec-tance | Case Study 3: Dimming Control with Two Separate Rows | Case Study 2: Dimming Control for All Luminaires | Case Study 1: On/Off Control with Two Separate Rows | ||||||

3.0 m | 30% | High | - | - | - | 36 € | −17 € | −70 € | - | - | - |

3.0 m | 60% | High | - | - | - | −43 € | −70 € | −96 € | - | - | - |

3.0 m | 90% | High | - | - | - | −63 € | −83 € | −103 € | - | - | - |

3.0 m | 30% | Low | - | - | - | 210 € | 99 € | −12 € | - | - | - |

3.0 m | 60% | Low | - | - | - | 20 € | −27 € | −75 € | - | - | - |

3.0 m | 90% | Low | - | - | - | −51 € | −75 € | −99 € | - | - | - |

6.0 m | 30% | High | 1716 € | 1063 € | 410 € | 1540 € | 986 € | 432 € | 745 € | 482 € | 218 € |

6.0 m | 60% | High | 350 € | 152 € | −45 € | 392 € | 221 € | 49 € | 152 € | 86 € | 20 € |

6.0 m | 90% | High | 113 € | −6 € | −125 € | 194 € | 89 € | −17 € | 72 € | 33 € | −7 € |

6.0 m | 30% | Low | 2488 € | 1577 € | 667 € | 1825 € | 1176 € | 527 € | 927 € | 603 € | 278 € |

6.0 m | 60% | Low | 1752 € | 1087 € | 422 € | 1540 € | 986 € | 432 € | 856 € | 555 € | 255 € |

6.0 m | 90% | Low | 802 € | 453 € | 105 € | 733 € | 448 € | 163 € | 405 € | 255 € | 104 € |

9.0 m | 30% | High | 2547 € | 1617 € | 687 € | 1659 € | 1065 € | 471 € | 1201 € | 785 € | 369 € |

9.0 m | 60% | High | 2824 € | 1802 € | 779 € | 2490 € | 1619 € | 748 € | 1121 € | 732 € | 343 € |

9.0 m | 90% | High | 1439 € | 878 € | 317 € | 1303 € | 828 € | 353 € | 587 € | 376 € | 165 € |

9.0 m | 30% | Low | 2298 € | 1451 € | 604 € | 1018 € | 638 € | 258 € | 951 € | 619 € | 286 € |

9.0 m | 60% | Low | 3438 € | 2211 € | 984 € | 2371 € | 1540 € | 709 € | 1711 € | 1125 € | 540 € |

9.0 m | 90% | Low | 4269 € | 2765 € | 1261 € | 3511 € | 2300 € | 1089 € | 1901 € | 1252 € | 603 € |

© 2018 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/).

## Share and Cite

**MDPI and ACS Style**

Acosta, I.; Campano, M.Á.; Domínguez-Amarillo, S.; Muñoz, C.
Dynamic Daylight Metrics for Electricity Savings in Offices: Window Size and Climate Smart Lighting Management. *Energies* **2018**, *11*, 3143.
https://doi.org/10.3390/en11113143

**AMA Style**

Acosta I, Campano MÁ, Domínguez-Amarillo S, Muñoz C.
Dynamic Daylight Metrics for Electricity Savings in Offices: Window Size and Climate Smart Lighting Management. *Energies*. 2018; 11(11):3143.
https://doi.org/10.3390/en11113143

**Chicago/Turabian Style**

Acosta, Ignacio, Miguel Ángel Campano, Samuel Domínguez-Amarillo, and Carmen Muñoz.
2018. "Dynamic Daylight Metrics for Electricity Savings in Offices: Window Size and Climate Smart Lighting Management" *Energies* 11, no. 11: 3143.
https://doi.org/10.3390/en11113143