ENERGY SAVING
What is LED – Light Emitting Diode
While incandescent bulbs use a lament and CFL’s use gas, LED’s produce light by exciting electrons. Put simply, within every LED bulb there is a semiconductor material filled with positively and negatively charged particles. When electricity strikes the semiconductor (the light is turned on), the electrons become charged and ow from the negative to the positive layer within the semiconductor. As they move, the excited electrons pass through “holes” in the material, which causes them to emit photons of light and illuminate the LED.
Benefits of LED
Longer Lifetime
Longer life time estimates stand out as the number one benefit of LED lights. LED lamps have an outstanding operational life time expectation of up to 50,000 hours. This is around 5.7 years of continuous operation. If you leave the LED fitting on for standard office hours, 8h per day 5 days per week, it would take an estimated 24 years before you would have to replace the LED bulb. Furthermore, LED’s are different to standard lighting in that they don’t really burn out and stop working like a standard light. The lighting diodes tend to emit lower output levels over a period of time and become less bright as opposed to full failure
More Effi cient
LED is currently the most efficient way of illumination and lighting, with estimated energy efficiency in the range of 80%-90% when compared to traditional lighting and conventional light bulbs. This means that about 80% of the electrical energy is converted to light, while a ca. 20% is lost and converted into other forms of energy such as heat.
LEDs are “directional” light sources which means they emit light in a specific direction, unlike incandescent and compact florescent bulbs which emit light and heat in all directions. For this reason, LED lighting is able to use light and energy more efficiently in many applications.
Energy and Maintenance Saving
LEDs use less energy to produce a similar lumen output to those of traditional lamps due to their greater efficiency. Less energy means immediate savings on energy usage costs. Furthermore, the longer lamp life of LEDs reduce the maintenance costs required to change out lamps that have stopped working.
Durable
LEDs are extremely durable and built with sturdy components that are highly rugged and can withstand even the roughest conditions. Since LED lights are resistant to shock, vibrations and external impacts, they make great outdoor lighting systems for rough conditions and exposure to weather, wind, rain or even external vandalism, traffic related public exposure and construction or manufacturing sites.
Lighting Quality
LED illumination produces little infrared light and close to no UV emissions. Therefore LED lighting is highly suitable not only for goods and materials that are sensitive to heat due to the benefit of little radiated heat emission, but also for illumination of UV sensitive objects or materials such as in museums, art galleries, archaeological sites etc. Furthermore, LEDs do not incur flickering effects. It’s a digital lighting technology that is tuned for 100% performance. This is the reason why there is no flickering, as experienced with some florescent lamps and makes them ideal for an office environment.
Environmentally Friendly
LEDs are made from non-toxic materials and will help you reduce your carbon footprint, unlike fluorescent lighting that uses mercury that may pose a danger to the environment. LED’s are also considered recyclable material and considered “green” or Earth-Friendly
Switching Eff ects
LED lights can be switched o and on frequently without affecting the LED’s lifetime or light emission. In contrast, traditional lighting may take several seconds to reach full brightness, and frequent on/o ff switching does drastically reduce operational life expectancy. This makes LED preferable for developments with high switching frequencies in locations operated by motion detection. In instances where motion detection is saving energy with traditional lamps, it is in fact also reducing the life of the lamp.
Comparison of LED with florescent and incandescent lamps
| ENERGY EFFICIENCY | LED | FLUORESCENT | INCANDESCENT |
|---|---|---|---|
| LIFE SPAN IN HOURS | 50,000 | 10,000 | 1000 |
| ENERGY USAGE IN WATTS (EQIVALENT 60W) | 5W | 11W | 60W |
| COST PER LAMP | €8.77 | €5.78 | €3.94 |
| ANNUAL ENERGY COST (€0.16 PER KWH) | €7.01 | €15.41 | €84.10 |
| BULBS NEEDED FOR 50,000 HOURS | 1 | 5 | 50 |
| COST OF BULBS & ENERGY FOR 50K HOURS | €15.78 | €44.31 | €281.11 |
| ENVIRONMENTAL IMPACT | LED | FLUORESCENT | INCANDESCENT |
|---|---|---|---|
| DURABLE | YES | NO | NO |
| CONTAINS TOXIC MERCURY | NO | YES | NO |
| CARBON DIOXIDE EMISSIONS (based on 3 lamps) | 198 kg/year | 463 kg/year | 1982 kg/year |
8W EMERGENCY EXIT/BULKHEADS
(Operational 24 hours a day, 7 days a week)
- An 8W T5 Fluorescent Lamp, allowing for 10% gear losses, uses 77.09 kWh per year
- At an average ESB rate of €0.16 per unit (kWh), plus 13.5% VAT, costs €14.00 annually for energy.
- A replacement 4W LED fitting, with 5% gear losses, uses 36.79 kWh, €6.68 annually
- Projected annual maintenance costs for 8W T5 is €14.83 (See note below on Maintenance Costings)
Annual Savings moving to LED €22.15
28W 2D FLUORESCENT FITTING
(Operational 24 hours a day, 7 days a week)
- A 28W 2D Fluorescent Lamp, allowing for 10% gear losses, uses 269.81 kWh per year.
- At an average ESB rate of €0.16 per unit (kWh), plus 13.5% VAT, costs €49.00 annually for energy.
- A replacement 15W LED tray, with 5% gear losses, uses 137.97 kWh, €25.06 annually.
- Projected annual maintenance costs for 28W 2D is €20.09 (See note below on Maintenance Costings)
Annual Savings moving to LED €44.03
5ft 2 x 58W T8 FLUORESCENT FITTING
(Operational 24 hours a day, 7 days a week)
- A 2 x 58W T8 Fluorescent Fitting, allowing for 10% gear losses, uses 1,117.78 kWh per year.
- At an average ESB rate of €0.16 per unit (kWh), plus 13.5% VAT, costs €202.99 annually for energy.
- A replacement 24W LED tube, with 5% gear losses, uses 220.75 kWh, €40.09 annually.
- Projected annual maintenance costs for 2x58W T8 is €22.81 (See note below on Maintenance Costings)
Annual Savings moving to LED €185.71
GU10 50W DOWNLIGHT
(Operational 24 hours a day, 7 days a week)
- A 50W GU10 Downlight, allowing for 15% gear losses, uses 503.70 kWh per year.
- At an average ESB rate of €0.16 per unit (kWh), plus 13.5% VAT, costs €91.47 annually for energy.
- A replacement 5W LED tube, with 5% gear losses, uses 220.75 kWh, €8.35 annually
- Projected annual maintenance costs for 50W GU10 is €16.00 (See note below on Maintenance Costings)
Annual Savings moving to LED €99.12
BOLLARD LIGHTING
(Operational on photocell – 11.5 hours a day, 7 days a week, in accordance with ESB daylight estimations)
- A 70W SON, allowing for 15% gear losses, uses 336.49 kWh per year.
- At an average ESB rate of €0.16 per unit (kWh), plus 13.5% VAT, costs €61.11 annually for energy.
- A replacement 9.5W LED tube, with 5% gear losses, uses 41.70 kWh, €8.35 annually.
- Projected annual maintenance costs for 50W GU10 is €16.00 (See note below on Maintenance Costings)
Annual Savings moving to LED €99.12
MICROWAVE SENSOR 
The sensor is an active motion sensor. It emits a high-frequency electro-magnetic wave (5.8GHz) and receives their echo. The sensor then detects changes in the echo from the slightest movement and switches on the fitting. As this sensor does not require line of sight to detect, it is the ideal solution for stairwells, corridors, car parks, utility areas or store rooms. The sensor will also be fitted underneath the fittings cover, hence will have no visual impact to the environment.
All savings will be dependent on the actual occupancy or footfall through a given area where the microwave will be operational. However, savings of up to 80% is possible in certain environments.
| On 24 hours | LED Fitting | LED Fitting with Microwave (20% occupancy) |
|
|---|---|---|---|
| 28W 2D | €49.00 | €25.06 (49% savings) | €5.01 (90% savings) |
| 5ft Fluorescent | €225.80 | €40.09 (82% savings) | €8.02(96% savings) |
NOTE: MAINTENANCE COSTINGS
- A fluorescent lamp has a specifi ed lamp life of 8,000-10,000 hours. With 8,760 hours annually, that’s a lamp change once a year on average.
- Average lamp life of LED is 30,000 to 50,000 hours (5 years).
- Projected average annual maintenance and repair costs include;
o Cost of replacement lamp
o Collection and delivery of replacement lamp
o Labour to replace lamp
Development Overview
Hampton Wood is a residential development in the Finglas area, consisting of 196 apartments spread over 12 blocks with an underground carpark.
Throughout the development the following lighting system was retrofitted;
- The Car Park consisted of 171, 2x58W fittings, operational 24 hr a day (8,760 hours a year)
- There were 161 no. – 28W 2D’s on photocell, operational for 4,150 hours a year (ESB Networks estimation)
- The remaining 253 no. – 28W 2D’s, were operational 24 hours a day
- There were 89 no. – 8W Emergency Exits, required to be on (fully maintained) at all material times.
- The external common area within the blocks consisted of 41 bollard lights, on photocell
Project Overview
The following works was performed by Lara;
- 28W 2D’s were retro tted to an LED 18w Tray with a microwave sensor for occupancy detection.
- 8W Emergency Exit Boxes were replaced with a 4W LED Emergency Exit Box.
- 2x58W 5ft ttings were re-wired to accommodate an LED tube and a microwave sensor was installed for occupancy detection.
- For 2x58W 5ft Emergency fittings, a non-maintained 3W bulkhead was installed to satisfy Emergency Lighting requirements.
- The Bollard lighting was retro tted to install 9.5W LED lamps.
- Microwave Detectors – Occupancy and Daylight detectors in one device. The sensor is an active motion sensor.
Project Summary
Project Savings
Annual Usage for Fully Operational Lighting System with Fluorescent Lamps
- 220,110.64 kWh @ Unit rate of €0.16 per kWh € 35,217.70 + VAT @ 13.5% €39,972.08
Annual Usage for Fully Operational Lighting System with LED Lamps
- 51,441.07 kWh @ Unit rate of €0.16 per kWh € 8,230.57 + VAT @ 13.5% € 9,341.69
Total annual savings
- Energy Savings of 168,669.57 kWh (Savings of 76%)
- Monetary savings of € 30,630.39
Project Timescale
From date of approval to project completion, the project lasted 29 working days
Warranty on new LED fi ttings
Lara obtained the contract for the emergency lighting maintenance for the development, for the duration of the three year term of the payback period. In obtaining the maintenance Lara guaranteed that no lighting remedial costs would be incurred for the customer whilst maintained by Lara. All fi ttings would be repaired or replaced on each quarterly maintenance visit.
Cost Neutral Payment Plan
Lara proposed a 3 year payback period, with monthly payments equal to those of the estimated monthly savings that were to be achieved when compared to a fully operational lighting system. In essence it was a cost neutral project for the development. This allowed the development to make dramatic savings and not have to outlay any payments as all monies due were to be paid from the savings made. In return the development also achieved a fully functioning and fit for purpose lighting system.
Grant Funding
The installation cost and payback period was further reduced by Lara seeking an Energy Grant from an Energy provider seeking energy credits for carbon emissions created through electricity generation. The Hampton Wood retrofit received a grant for €9,376.74 plus VAT @ 23%. This credit was passed on in its entirety to the development and reduced the cost of installation.
Development Analysis
Key Points
- Construction of the development was concluded in early 2008. It is assumed that all lights were fully operational during this ESB reading period. Thus the average daily energy usage for a fully operating lighting system is 603.04 kWh per day for the entire development.
- Point 1-2 – The oscillation of the energy curve coincides with the variance in daylight hours throughout the year. The initial reading in Feb-08 is for the winter 07 period up to February, were the lights on photocell are operating for the peak amount of time, to Point 1 in Jun-08 the summer months with the least amount of energy usage. The curve then begins to peak again to Point 2 the winter months of 2008.
- Point 3 – The energy curve begins to peak for the winter months in 2009 similar to above. However the energy usage is less to the previous year due to lamp and fitting failures.
- The average fluorescent lamp life is 10,000 hours. There is 8,760 hours in a year, hence a lamp typically need to be replaced once a year. The lamp life of a fl uorescent lamp is further shortened by frequent switching operations. Thus the introduction of motion detection, albeit saves energy in turning off the light, shortens the life of the lamp.
- Point 4 – During the survey for the initial proposal for the retrofit to LED, it was found that throughout the development 55% of the development had lamp or fitting failures
- Note that all energy usage is not Actual Readings, whereby some readings are ESB Estimations. Therefore whilst not always exact readings for the data above, the curve is a close approximation.
- Note that the readings at the start and end of the graph are “Actual Reading”, whereby thereadings were read off the meters.
SAMPLE BLOCK 1: 100 – 113 Hampton Wood Avenue
USAGE BEFORE RETROFIT
- ≈ 60% of lights working
- Total usage for 62 day period – 971 kWh
- Projected usage if all lamps were working for same period – 1,618.33 kWh
Block consisted of:
- 7 x 8W Emergency Exits
- 36 x 28W 2D’s (12 on photocell)
USAGE AFTER RETROFIT
- 100% of lights working
- Total usage for 61 day period – 405 kWh
Block consisted of
- 7 x 4W Emergency Exits
- 36 x 18W LED 2D Retro t Trays