Lighting, Daylighting & Integrated Design

Arihant Jain Lighting, Daylighting and Integrated deign lab M.Tech Building Energy Performance CEPT University Sep 2017 Monsoon Semester Arihant Jain

Lighting, daylighting and integrated design lab

Page- 1

Measuring light Intent The intent of the assignment was to develop an intuitive understanding of illuminance levels & to understand the working of light in a space.

Inference Understanding of calculating reflectance of materials by measuring illuminance & luminance.

Understanding of the behavior of light due to source, modifier & task.

For the first part of the assignment, a material reflectance library was developed In the second part, the daylight penetration was observed and the impact of artificial light was calculated.

Material library & daylight penetration

Arihant Jain

Lighting, daylighting and integrated design lab

Page- 2

Measuring light Reflectance of Light We measured the illuminance falling on different surfaces and the exitance of light from different surfaces using a Kusam – Meco KM-Lux-99 digital Lux meter.

After measuring illuminance & exitance, we calculated the reflectance for each material and created a material library, which we used for simulation exercises.

The colour and texture of the material were also noted for better understanding.

The basic idea about lambertian and specular surface was also introduced to us, as we also took readings from specular surfaces with the lux meter, which were wrong.

Different materials from the library created

Illuminance We placed Hobo data logger & sensor to measure horizontal & vertical daylight illuminance levels near a window in FM203. We assessed the impact of nearby modifiers to understand the variation in illuminance levels recorded by each sensor. As a part of this assignment, we also measured illuminance (artificial + daylighting & only daylight) for FT – 101 class. After measurements, we analysed daylight performance and calculated artificial light illuminance.

Daylight penetration in FT 101 Arihant Jain

Lighting, daylighting and integrated design lab

Placement of loggers Page- 3

Developing lighting schedules Intent This assignment intent was to develop a baseline for lighting usage and occupancy patterns for lighting energy calculations & simulations. This was done by monitoring the lighting usage patterns for the assigned spaces using Hobo loggers.

Inference The assessed room had adequate daylight during the daytime, and hence artificial light was rarely used.

The Lighting power density (LPD) of the room, the peak lighting energy use, and the total cooling load due to lighting was found.

Logger placed on wall

Logger placed just above the luminaire

Logger locations in FT 101 & graph indicating the daily energy consumption due to lighting.

Arihant Jain

Lighting, daylighting and integrated design lab

Page- 4

Developing lighting schedules Methodology

Results

The room allotted to us was FT 101 for the measurements. There were 18 T8 lights installed in the rooms.

•

The artificial light is not used during the daytime due to adequate amount of daylight from north light.

•

The peak lighting energy use of the given space is 43.65 Wh.

•

The LPD of the space is 11.34 W/m2.

Logger placed just above the light fixture

The loggers were to be placed in such a manner that they can easily read the jump in illuminance levels when the lights are switched on.

Luminaire Logger 2 place on the wall

On the basis of measurements taken over a period of 1 week, the data was analyzed and lighting schedule was developed. The data was used to calculate various energy consumption patterns.

Logger locations in section

Notes •

Current transducer & True RMS AC Voltage/Current Data logger were used to determine the energy consumption of lights in the space.

•

The energy consumption could not be directly calculated by the wattage mentioned on the fixture as it does not take into account the ballast factor.

•

Hence, we measured the energy consumption of one of the fixture, and multiplied by the number of fixtures in the room.

Logger 2 Logger 1

Logger locations in plan Arihant Jain

Typical, peak and hourly average for weekdays and weekends Lighting, daylighting and integrated design lab

Page- 5

Electric lighting retrofit: simulation in DiaLux Intent This assignment was divided into 3 parts: 1. We gave a critique for the existing lighting design through measurements and visual observations for FT – 101 class.

2. We used unified facilities criteria (UFC) – Interior and exterior lighting systems and controls to set the design criteria & recommendations for the classroom.

3. We explored multiple design solutions using DiaLux simulations to meet our set criteria.

Inference

We were able to give a critique on existing lighting layout on the basis of illuminance levels at task (Measured) and reflectance of surfaces (visual observation).

We tried parametric variations for meeting the set criteria.

We got an understanding of the impact of reflectance of surfaces, the layout of luminaire, the height of luminaire, and the type of luminaire on various parameters of light like average illuminance and uniformity.

Arihant Jain

DiaLux views

Lighting, daylighting and integrated design lab

Page- 6

Electric lighting retrofit: simulation in DiaLux Existing Lighting Design critique

Design criteria & recommendations

We made a model of the existing classroom with furniture layout in DiaLux.

The design criteria & recommendations were set up by using UFC as our guideline. The different lighting design solutions we came up with were:

We applied materials with different reflectance for all the surfaces, and set then fixed the work plane at 0.85m.

1. Increasing the reflectance of surfaces 2. Modifying the luminaire layout

After that, we installed appropriate luminaire with similar specifications (installed in classroom) at same positions with similar modifiers, and simulated them.

3. Modifying the luminaire height from the ceiling 4. Modifying the luminaire & layout.

False color results for base case

Base Case On simulating, a base case for comparing the parametric variations was produced.

The comparison was done on the basis of maximum, minimum, and average illuminance, and uniformity ( Minimum / average).

Luminaire Position

The results for the simulated base case were very poor, and were below the UFC standards.

Luminaire position for base case Arihant Jain

Lighting, daylighting and integrated design lab

Page- 7

Electric lighting retrofit: simulation in DiaLux Changing reflectance

Modifying layout

Changing luminaire height

The reflectance of walls, floor and ceiling were increased.

The existing layout was changed and the number of luminaires was reduced from 18 to 9 for this case. This case focused on providing luminaires just above the task plane, and not in the ambient spaces.

This modification was done as given by the UFC design criteria. For this case, 3 luminaire heights from the ceiling were given: 457mm, 914 mm, & 1.2m below the ceiling.

The average illuminance dropped by 21%, where as the uniformity increased by 191.7%

As the luminaires came near to the task, the average illuminance increased, but the uniformity decreased.

The change in reflectance caused the average illuminance to increase by approximately 4%, and the uniformity increase by approximately 17%.

False color image by changing reflectance Arihant Jain

Modifying layout - results Lighting, daylighting and integrated design lab

Modifying height - results Page- 8

Using artificial mirror box sky Intent The main aim of the assignment was to observe and understand the daylight implications inside a space on a work plane in overcast sky conditions

Inference

1

8

2

9

3

10

4

5

6

7

12

13

14

15

We tested out different window types with same window to wall ratio (WWR) of 30% in mirror box, and took 15 readings inside the box model.

We found that the clerestory windows help in better penetration of daylight The light shelves do not significantly help in increasing illuminance levels.

On the contrary, they can reduce the average illuminance levels inside a space. They help in providing better uniformity.

Mirror box sensors; designed opening types; scale model for mirror box experiment Arihant Jain

Lighting, daylighting and integrated design lab

Page- 9

Using artificial mirrorbox sky Cases •

•

We made a total of 8 types of fenestrations.

They were divided into 3 groups: •

4 cases with different size of openings/position with same WWR.

•

3 cases for same opening – one with no light shelf, and 2 with light shelf with specular & lambertian surface.

•

3 cases for clerestory opening – one without light shelf, and 2 with specular and lambertian surface.

The parameters analysed were maximum, minimum, and average illuminance, uniformity, and daylight factor.

Comparative analysis

Daylight penetration

Methodology •

We made a scale model of dimensions - 8 x 12 x 3m; with WWR of 30%, and 0.75m as the work plane height, and the interior surface was covered with white sheet (82% reflectance. For light shelf, lambertian and specular type were made and used.

•

The 14 sensors were placed inside the model in 2 rows, and one sensor was placed on top of the model to measure outdoor illuminance level. A set of 6 readings were taken from each sensor, and a python script was used to run the simulations.

•

The simulations results were recorded in a text file, which were imported into excel for plotting graphs and comparing results. The daylight factor was the most appropriate metric for comparing performance of the windows.

Window types Arihant Jain

Lighting, daylighting and integrated design lab

Page- 10

Optimizing for daylight factor Intent This assignment was divided into 3 parts: Daylight pattern guide website was used for reviewing in terms of daylight, and the various parameters which affected daylight were analyzed.

By using an excel tool (B3 tool), various parametric were performed to achieve a given condition.

Various daylight metrics were to be explained

Inference Impact of changing reflectance of different materials, changing window to floor area ratio (WFR), and the height of window could help achieve the required targets.

B-3 tools results; excel analysis; Daylight pattern guide

Arihant Jain

Lighting, daylighting and integrated design lab

Page- 11

Optimizing for daylight factor Building Geometry & Daylighting Multiple building with different types of floorplates were given on the Daylight pattern guide website (http://patternguide.advancedbuildings.net/patterns).

We had to observe them and review them on the basis of daylight performance.

The data given was related to the orientation of the buildings, some notes about the building, floor plate area, perimeter length, maximum distance to perimeter, point – in – time illuminance on sunny and cloudy day and a picture of the building.

Observation The building with deeper floorplate had bad daylighting (below 300 lux), and the narrower the floorplate, the better the daylight penetration (up to 300 lux).

Architects have tried to narrow down the floor plates by using central courtyard plans, and fingerlike plans.

The orientation of the building should be carefully considered (not the case with some of these buildings) to avoid glare and appropriate shading must be provided.

The point in time is not an appropriate metric for comparing daylighting in the buildings.

Daylight pattern guide details Arihant Jain

Lighting, daylighting and integrated design lab

Page- 12

Optimizing for daylight factor Window optimization for daylighting For achieving the given targets, reflectance of walls and ceiling was increased from 50 to 70% and 75 to 85% respectively, & the visible transmittance was increased from 50 to 70%.

Another alternative approach to achieve the target of 2% daylight factor in 75% of the room, and not have more than 10% of the floor area exceed the maximum uniformity ratio was by (modifying the WWR) from window area of 65 sq.ft. to 120 sq.ft. .

B-3 tool results

Data interpretation By increasing the window area by two times, the target was achieved.

Introducing a clerestory window gave a wider, uniform and deeper penetration of light.

Daylight penetration

Parametric analysis Arihant Jain

Lighting, daylighting and integrated design lab

Page- 13

Daylight simulation: Calibration & targets Intent The assignment given was to explore LightStanza.

This assignment was divided into 2 parts: To find Daylight autonomy (DA), spatial daylight autonomy (sDA), and annual sun exposure (ASE).

To achieve given target for same model: 75% sDA 300, 50% with <10% ASE 1000, 250

Inference The given targets were achieved by increasing the VT, by adding blinds, from both, and North and south direction.

The simulation results from the mirror box experiment were similar to that of the artificial sky emulator.

LightStanza model & Scale model Arihant Jain

Lighting, daylighting and integrated design lab

Page- 14

Daylight simulation: Calibration & targets Achieving performance targets For the first part of the assignment, daylight factor(DF) was compared for mirror box results & LightStanza results. For mirror box experiment, the average DF was 4.86%, and for LightStanza model, the average DF was 5.33%. The results are close and are acceptable within marginal error.

For the second assignment, the performance target are met by (for both North & South face): • Changing the transmittance from 50% to 75% • Providing venetian blinds (300) Also, The daylight glare probability (DGP) was found to be 28.1%, which is within the acceptable range.

Daylight factor for LightStanza model

Model calibration Model was calibrated to these settings: Sky Type – Overcast (For Daylight Factor), Climate ( For all other simulations) Quality: High Grid/Point Spacing: 600 mm o Location – CEPT University (23.04 , 72.55o) Occupancy: 8 AM to PM Method: Three-Phase Material Reflectance (Interior) : 80% sDA & ASE results Arihant Jain

Lighting, daylighting and integrated design lab

Daylight Glare Probability Page- 15

Exploring lightwells and borrowed daylight Intent The assignment was done majorly in two parts: â&#x20AC;˘ Light well analysis â&#x20AC;˘ Borrowed daylight analysis For each one of them, presets were given and we had to provide realistic solutions for increasing daylight penetration for both the parts.

Inference

For light well, it was observed that the illuminance levels on the northern interior wall were twice as that of the southern wall.

Three different window types were introduced on the southern side to make the light penetration more uniform on the horizontal surfaces.

A clerestory window performed best for providing uniform light distribution on the southern portion of the floor plate.

For borrowed daylight, the results showed that the illuminance levels inside the interior room which received borrowed daylight was one-hundredth as that of the rooms with direct opening to sky.

Light well & borrowed daylight model & results Arihant Jain

Lighting, daylighting and integrated design lab

Page- 16

Exploring light wells and borrowed daylight Borrowed daylight To increase the illuminance of borrowed daylight in the interior room, we increased reflectance, VT, and window area.

We were able to achieve maximum average illuminance levels of 88 lux inside the room, but in the rooms outside, the average maximum illuminance was 7824 lux, which is very high and can cause glare and increased heat gain through the windows.

Window parametric

Results

Exploring light wells

•

The light wells provided more illuminance levels on the northern horizontal surface as compared to the southern surface. Hence, we had to increase the penetration and uniformity, which we achieved by providing windows on the South.

•

Three strip window configurations were tested out:

• Borrowed daylight model Arihant Jain

•

2 m height & 1 m sill,

•

1 m height & 1 m sill,

•

and 1 m height & 2.5 m sill (clerestory)

Best results were achieved by clerestory window, with a penetration of up to 8.4 m for 300 lux on the ground floor.

Lighting, daylighting and integrated design lab

Page- 17

Whole Building Simulation Intent The goal of this problem was to improve an ECBC compliant bank institute into a more energy efficient building. Also, the impact of each building performance parameters had to be assessed, and the energy conservation measures had to be chosen accordingly. The impact of each ECM had to be reflected in terms of energy and cost savings.

Inference The given building had a very less impact on its energy consumption by optimizing the building envelope. Highest savings were achieved from daylighting controls and LPD reduction. These helped in reducing the lighting loads as well as the HVAC loads. Due to this, significant reductions were achieved in demand load and overall energy consumption, hence giving more savings.

Sun path diagram laid out on the Building Arihant Jain

Lighting, daylighting and integrated design lab

Page- 18

Whole Building Simulation Climate Analysis Climate Analysis of Pune was done, and potential for passive strategies was identified. Shading analysis of the existing shading devices was done. Daylighting analysis for the existing conditions (WWR, glazing, shading) was done in LightStanza.

Useful Daylight Illuminance (UDI) and Daylight Autonomy were analyzed for the existing building.

ECBC compliance The base case for comparing the results was taken as an ECBC compliant building. So, ECBC was read & understood thoroughly for minimum requirements, and the base case model of this building was made ECBC compliant for simulation.

The resultant performance of the building had to be better then the ECBC compliant base case.

Shading Mask; Temperature hourly graph; Daylight Autonomy; Monthly energy consumption graph of base case Arihant Jain

Lighting, daylighting and integrated design lab

Page- 19

Whole Building Simulation Elimination Parametric Multiple elimination parametric runs were performed to assess the savings potential from each measure. These runs indicate the impact of eliminating the loads on Energy Use Intensity, peak loads, cooling loads and all other energy and cost savings.

Through these runs, the priority of ECMs’ was decided according to their impact on various parameters. A total of 9 EP runs were done.

Energy Conservation Measures The ECMs’ are decided on the basis of EP runs. The savings potential from each ECM was analyzed in terms of cost and energy. The ECM related to light (Daylight control & LPD reduction) gave the maximum load reduction and savings. Annual savings from each ECM was calculated and the ECM were ranked according to the savings they gave.

End Use split of EUI for all elimination parametric runs; Annual Energy savings for all ECMs’ Arihant Jain

Lighting, daylighting and integrated design lab

Page- 20