Duke LED Initiative Duke Smart Home- In-Progress Document1

Anuj Thakkar, Aashna Aggarwal, Lara Breitkreutz, Gouttham Chandrasekar, Yutao Gong

Introduction Education facilities are perpetually seeking to reduce operating costs, and because energy

consumption is a significant operating cost, facilities are often seeking strategies to reduce energy

consumption.

LED Direct Fit Technology, a new solution, is only recently becoming known by many energy-

auditors and facilities managers. By focusing on this single technology to replace fluorescent tube-lighting, we

will significantly reduce electricity consumption, and therefore operating costs.

Duke University’s Hudson Hall, which contains an estimated ~3688 candidate tube-lights, is the base

for our pilot initiative. Duke University also has a commitment to reach climate neutrality by 2024. Our

initiative, if implemented on a larger scale, would help Duke make progress towards this goal.

Our Goal:

-Change all 32W 4ft T8 lamps (~3688 lamps) to 17W Philips LED 4ft T8 lamps in Duke University’s

Hudson Hall

-Use this success as a model for larger scale implementation across Duke’s campus

In Hudson Hall, our Calculations Show: $183,017 electricity savings over 50,000 hours (15 years).

182,556kWh annual energy reduction. 1.6 years Return on Investment Period

$21,833 Initial Materials Cost Project Timeline: January, 2017:

-Receive and Install 50 Bulbs ordered by Ani J with Kevin Curry -Establish FMD contribution with Abhi Bathula, finalize labor costs, and purchase LEDs. -Install photosensors provided by FMD in Hudson Hall for three weeks. -Present work to the Campus Sustainability Committee -Develop a plan to acquire, if not acquire, funding for full initiative

February, 2017 -Acquire funding for full initiative. -Purchase lighting materials for full implementation. -Finalize installation schedule for long weekends and Spring Break 1*This document is an update from a previous version. The previous version had slight differences in lighting quantities and included

another brand that is no longer analyzed in this document.

Current Lighting Details Fluorescent Tubes Many, if not all, Duke facilities currently use fluorescent tube-lighting to light classrooms, hallways, and

offices. These tube-lights are sold by several companies such as EcoLux, Philips, and GE, and the tube-lights

vary in color, lifespan, wattage, Color-Rendering-Index (CRI), lumens, and cost.

Lifespan: Typical low-cost fluorescents have an average rated life of 20,000 hours, though higher- cost

fluorescents have longer lifespans.2 While additional data is required, our team has observed “Philips 700 Series” fluorescents and “Ecolux Long-life,” which have 36,000-hour and 40,000-hour lifespans,

respectively.34

Wattage: Most fluorescent tubes are 32Watts, though 25W and 28W brands exist. The following chart,

provided by The Lighting Research Center, displays comparisons between various 32W Fluorescent tubes by one

manufacturer.

http://www.lrc.rpi.edu/programs/nlpip/lightinganswers/t8/09-t8-cost.asp

RE(#) refers to the CRI of tubes. For example, RE80 tubes have a CRI in the 80s.

a. The Philips 700 series tube has a CRI of 78.

b. The Ecolux Long-Life tube has an unknown CRI.

Lamp Efficacy is measured by “Lumens per Watt”

a. The Philips 700 series has a LPW of (81).

2http://www.lrc.rpi.edu/programs/nlpip/lightinganswers/t8/09-t8-cost.asp

3https://www.amazon.com/Philips-281576-F32T8-Lumens-Phosphors/dp/B0094GX0UI4http://premierlightbulbs.com/ge-68854-f32t8-xl-spx30e2-4-foot-t8-32w-3000k.html

b. The Ecolux Long-Life tube has a LPW of (91).

While the Philips 700 series tubes range in price (up to $3 per tube), and the Ecolux Long-Life tubes

range in price (up to $5 per tube), we acknowledge that there are variations in performance and costs of tubes

on campus. For our calculations, we have assumed high-performance fluorescents at low costs. This allows

for our calculations to be “worst-case-scenario,” and means that cost savings will likely be higher with official

data on campus tube-lighting.

Our reference tube:

-32Watt -36,000-hour lifespan -$1.69/tube

(Deviations from this will be noted in the document)

LED Tubes There are various brands of LED tubes on the market. We have not considered LED Retrofit lamps that

require replacing entire lighting fixtures due to expected significant time, labor, and fixture costs. We focus on

a new technology, LED direct-install tubes, which allow users to simply change fluorescent bulbs with LED

bulbs without re-wiring fixtures. Our analysis has narrowed our search to the 17W Philips

Daylight/CoolWhite T8 Tubes.

17W Philips Daylight T8 Tubes:

-Wattage: 17W

-Cost: $5.92 / bulb (before large bulk-pricing)

-Lifespan: 36,000 hours

-CRI: 82

-LPW: 123.52

-Lumens: 2100

-Note: while lumens are lower, because LEDs are directional, actual brightness received by the rooms are

higher. (Lux measurements have been taken previously—more info in person)

Bulb Warranty Information Fluorescent Warranty: (30 Months)

Similar Brand: https://www.1000bulbs.com/product/85821/PHILIPS-281576.html

17W LED Warranty: (48 Months) **Check

http://images.philips.com/is/content/PhilipsConsumer/PDFDownloads/United%20States

/ODLI20160815%5F001%2DUPD%2Den%5FUS%2DPhilips%2DWarranty%2DComponents%2

DNorth%2DAmerica%2DAugust%2D2016.pdf

Calculations for Annual Time-Usage of Lights (Calculated with info from Kevin Curry, Associate Director of Facilities for the Pratt School of Engineering) Room Type Hours / Year Bulb Quantity Private Office: 1962.5 **(820) Classroom: 2600 **(1640) Labs: 3225.6 736 Hallways: 8760 482 *Restrooms: 8760 10 *Restrooms do not contain 4-foot fixtures. **Exact figures not currently known. Calculated this quantity assuming a 2:1 ratio of Office:Classroom lights in Hudson Hall, and bulb-counts at that time Weighted Average of Light Consumption in Hudson Hall based on Room Type, Quantity, Hours/Yr:

((8760 * 482) + (3225.6 * 736) + (1962.5 * 820) + (2600 * 1640)) (736 + 482 + 2460)

Result: 300 days/yr, 11.3 hrs/day. We have rounded to 11hrs/day for all calculations. Total Cost of Operation of One Bulb (-Labor, Maintenance costs not included -Electricity/Bulb Price Changes not estimated) (Values rounded to the nearest whole)

**Used 30,000 hour lifespans vs. 36,000 hour for calculations. (Numbers displayed will be the similar, due to

costs being shown at 10,000hour intervals).

Total Cost of Operation of 3688 Bulbs over 50,000 hours (-Labor, Maintenance costs not included -Electricity/Bulb Price Changes not estimated) (Values rounded to the nearest whole)

**Used 30,000 hour lifespans vs. 36,000 hour for calculations. (Numbers displayed will be the similar, due to

costs being shown at 10,000hour intervals).

Additional Calculated Values for Hudson Hall Summary

-3688 17W LED Tubes -Return on Investment: 1.6 years -Projected Lifespan: 10.9 years -Initial Materials Cost: $21,833 -Annual Energy Reduction: 182,556kWh -Annual Cost Savings: $13,600

**The following do not account for purchasing a new set of LEDs at end of LED lifespan and a new set of fluorescents at end of fluorescent lifespan, hence discrepancies in savings from above)

Calculations for 17W LED:

Equations for Calculations (Note: Hours to Years Conversion is performed pre-analysis)

LEy = Yearly Energy Consumption of LED Tube LCy = Yearly Energy Cost of LED Tubes

FEy = Yearly Energy Consumption of Fluorescent Tube

FCy = Yearly Energy Cost of Fluorescent Tubes

ESy = Yearly Energy Savings CSy = Yearly Cost Savings

CL = Up-Front Cost of LEDs

LEy = [Energy Consumption / Hour] * [0.001 (for kWh conversion)] * [Hours Used / Day] * [Days Used / Year] * [Number of Tubes Replaced]

LCy = [Energy Cost] * LEy FEy = [Energy Consumption / Hour] * [0.001 (for kWh conversion)] * [Hours Used / Day] * [Days Used / Year] * [Number of Tubes Replaced]

FCy = [Energy Cost] * FEy ESy = FEy - LEy CSy = FCy - LCy Return on Investment: CL = Time * CSy