Project Description
LDP Ltd undertook a feasibility study for Waitakere City Council (now Auckland Council) in 2009, considering options to light a pedestrian traffic route through Olympic Park as one element of a route linking residential areas to New Lynn town centre.
Concept and Brief
LDP Ltd undertook a feasibility study for Waitakere City Council (now Auckland Council) in 2009, considering options to light a pedestrian traffic route through Olympic Park as one element of a route linking residential areas to New Lynn town centre, including the New Lynn rail-bus interchange. The study examined a variety of luminaires, lamps technologies, power supply alternatives and sustainability elements.
This resulted in a decision by Council to proceed with an off-grid solar powered lighting installation using LED luminaires for the majority of the pathway lighting.
In particular, Council initially provided the following brief to LDP;
- Provide good quality lighting (lighting design category P2 to AS/NZS1158)
- Use solar power (i.e. no power from the grid)
- Minimise obtrusive light effects beyond the park
- Consider sustainable practices in equipment selection
Council also subsequently agreed to the following LDP recommendations;
- Use recycled aluminium columns.
- Reduce illumination to P3 during periods of the night when activity levels are expected to be low.
Limitations
The solar engine needed to be designed to ensure that the lighting design levels were maintained throughout the agreed operating times at all times of year and throughout the anticipated life of the equipment.
The mass and windage of the solar engine and luminaire package needed to be minimised in order to minimise the size of the columns. This was particularly an issue for aluminium columns which have less strength than equivalent steel columns. Even so, the diameter of the columns needed to be 200mm.
In keeping with CPTED (Crime Prevention Through Environmental Design) principles, the lighting system needed to provide useful light several metres either side of the path, white light with good colour rendering and good visual comfort (low glare).
The Waitakere City Council District Plan required that the luminaires emit no direct upward light.
Maintain safe clearances from 110kV and 220kV overhead transmission lines. A specialist consultant in this field was engaged to ensure safe clearances were maintained.
Extent
The project extent being submitted includes the full length of the pathway linking the two roadside carpark areas. It excludes the carparks and the two ‘wind+solar’ pilot study lights as these areas are incomplete. The high pressure sodium lighting visible in the images is from the nearby and unrelated street lighting.
Lighting Concept
The lighting concept required an integrated lighting-power-control solution designed to be aesthetically pleasing in daytime while providing good quality lighting with good visual comfort at night. The lighting concept is founded on the principles of CPTED and sustainability.
This meant keeping the structures as close to human scale as practical, while having sufficient height to provide an economical means of achieving the P2 design category.
The luminaires are mounted at 6m. While the solar engine is higher, at night, the luminaire height tends to establish the perceived height of the structure. In addition, the dark grey colour chosen for the columns is recessive at night helping to minimise the visual impact. The overall result is that the installation does present as being human scale.
The lighting concept required an integrated lighting-power-control solution designed to be aesthetically pleasing in daytime while providing good quality lighting with good visual comfort at night. The lighting concept is founded on the principles of CPTED and sustainability.
This meant keeping the structures as close to human scale as practical, while having sufficient height to provide an economical means of achieving the P2 design category.
The luminaires are mounted at 6m. While the solar engine is higher, at night, the luminaire height tends to establish the perceived height of the structure. In addition, the dark grey colour chosen for the columns is recessive at night helping to minimise the visual impact. The overall result is that the installation does present as being human scale.
Architectural Integration
The street lighting columns recently installed for the adjacent New Lynn town centre have a dark grey finish. In order to provide visual continuity, this colour was continued into the pathway lighting equipment as much as possible. The recycled aluminium columns by their nature needed to have a substantial diameter (200mm) for strength. The dark finish helps to minimise the visual impact of the columns.
In addition, the chosen equipment has the solar panel, controls and luminaire integrated as one elegant package at the top of the column. This provides optimal integration of the various elements and removes the need for additional ground level boxes or unsightly additions to the column sides.
Originality
While we understand that the system has been used previously for flagpole lighting, this is the first application in New Zealand of the Carmanah Evergen solar lighting system for functional pathway lighting, and one of the first for the SAPA recycled aluminium columns. It is a significant project on the world stage for both companies and required a custom design from SAPA to accommodate the structural requirements of the Carmanah equipment.
Unlike many other solar lighting solutions, the system is designed to achieve;
- Specific design lighting levels during all hours of operation while being completely off the grid.
- Good quality lighting with minimised environmental effects.
- Integrated luminaire – solar engine design to optimise efficiency.
- Integrated operating profile and astronomic clock to optimise efficiency and minimise light pollution by reducing direct and reflected light at off-peak times.
Solution
SOLUTION
The selected luminaire was the Ruud Edge 40 LED, version C, with a type II distribution and 4300K colour temperature. The mounting height for the luminaires is 6m and the maximum spacing is 19m.
Design Criteria
The design has met all of the design criteria;
-
- Maintenance factor – There is much debate in the industry regarding suitable design criteria for LED lighting given the exceptionally long predicted life. We understand that IESNA is proposing using L70 to determine the useful life (i.e. the age at which the luminous flux output falls to 70%). Hence, we have used a lamp depreciation factor of 0.70. Similarly, as the luminaire is IP6x and since the locality would be considered ‘medium pollution’, we have assumed the longest cleaning cycle of 48 months in table F1, AS/NZS1158.1.3. Hence, the overall maintenance factor used = 0.70 x 0.84 = 0.59.
- Dimming profile – The controls are factory set for the Carmanah “5-DIM-2” profile – 100% output for 5 hours after dusk and 2 hours before dawn – 25% output for the remaining night-time hours.
- Results:
| PARAMETER |
PEAK TIMES (P2) |
OFF-PEAK TIMES (P3) |
||
|
TARGET |
CALCULATED | TARGET |
CALCULATED |
|
| Average (Ehavg) | ≥ 3.5 lux | 5.3 lux (*) | ≥ 1.3 lux | 1.3 lux |
| Minimum (Eh) | ≥ 0.7 lux | 1.8 lux (*) | ≥ 0.22 lux | 0.45 lux |
| Uniformity (UE2) | ≤ 10 | 1.5 | ≤ 10 | 1.5 |
| Vertical (EPv) | ≥ 0.7 lux | 1.0 | ≥ 0.22 lux | 0.25 lux |
(*) In order to achieve the P2 minimum vertical illuminance requirements, the horizontal minimum and average values are higher than required. However, the higher values are also necessary to ensure that P3 requirements are met when the system dims to 25%.
Check measurements have been taken confirming that the initial values relating to these calculations have been achieved.
Glare is the most important element to consider for Visual Comfort. IESNA Technical Memorandum TM-15 has established a rating system for outdoor lighting known as the ‘BUG’ system, which stands for Backlight, Uplight & Glare. Each element is rated on a scale of 0 (best) to 5 (worst). The luminaires used for Olympic Park have a B1-U0-G1 rating. Hence, the Glare rating value of 1 is very good.
As indicated by the calculations above and as evidenced in the images, the uniformity is excellent.
The luminaires have neutral colour temperature of 4300K and good CRI (minimum 75). Combined with placing the luminaires well above standard viewing angles, the resulting effect is indeed visually comfortable.
Energy Effectiveness
In terms of impact on the national grid, the result is zero. In other words, the energy effectiveness is optimal.
The installation utilises the most efficient product available on the market at the time with the equipment features and colour temperature chosen.
Budget Restrictions
During the feasibility study, it was estimated that the capital cost penalty for solar over a reticulated power would be in the order of 20%. Council accepted this as a reasonable premium for a sustainable lighting system. The budgets were set based on our estimates, tendered and delivered within the final agreed budget.
Operation and Maintenance
The system operation is fully automatic. Each Evergen unit has an astronomical clock and daylight sensing. No adjustments are required for the life of the units.
The system is very low maintenance. The LED lamps, electronics, solar engine and columns are all estimated to have a service life in the order of 20 years and all have 5 year limited warranties. The only component that is expected to require replacement is the long life battery with a nominal 5 year life.
Periodic cleaning of the photovoltaic panels and luminaires is also recommended as with most outdoor equipment, to maintain efficiency and finishes.
The Design
The increase in usage of the pathway in the evenings is testament to the success of the system. The lighting provides a pleasant ambience and good visibility along the pathway and a few metres either side, encouraging use through safety.
Lighting Equipment
In order to achieve the required lighting performance, optimise efficiency, minimise maintenance and provide a good aesthetic result, the Advanced Lighting Technologies Carmanah Evergen 1710 off-grid solar LED lighting system was chosen. This was complemented with custom designed SAPA recycled aluminium columns to maximise sustainability. Carmanah are based in Canada and SAPA in Holland.
The lighting equipment, as an integral solar-lighting device, was unique at the time of design in terms of the direct integration of LED driver electronics optimised for energy efficiency. We understand that this is still the case.
Pathway lighting is also a very good application for LED’s as the relatively limited spread of light required is suited to the precise nature of the photometric distribution produced by the lamp/luminaire combination relative to equivalent discharge lamp systems.
In addition, the Ruud Edge luminaire as used in the Carmanah Evergen 1710 system, presents an elegant appearance along with very effective optical control.
Innovation
This installation leads the way in a number of respects;
- The first use of the Carmanah Evergen 1710 solar lighting system in New Zealand for pathway lighting.
- A rare example of a purely solar powered lighting system that achieves good quality functional lighting to a recognised standard and does so all night, every night, regardless of weather conditions.
- A rare example of using recycled aluminium columns – unique in terms of the custom design required to accommodate the windage and mass of the Evergen system.
- Zero impact in terms of operation on fossil fuels, CO2 and greenhouse gas emissions.
Cost
The cost of the system as delivered was within the budget agreed with the client.
Efficiency
As the system has no connection to the grid, the efficiency relative to the grid is actually infinite.
The directional nature of the LED lamps means that for this application, we were able to use a lower system wattage than would have been required for an equivalent lighting result using metal halide lamps. The required 70 watt metal halide lamp would result in 80 system watts. The LED solution uses 68 system watts. This represents a 15% energy saving.
The off-peak automatic dimming systems save approximately 30% of the system energy that would otherwise be required
These savings help in minimising the size of the photovoltaic panels and storage batteries.
Maintenance
The system is maintenance free other than for replacement of the long life storage batteries (approximately 5 yearly) and recommended occasional cleaning as for any outdoor surfaces.
Recyclability
The lighting columns are at least 95% aluminium (typically testing in excess of 98%), which is fully recyclable. The columns themselves are mostly recycled aluminium.
At least 95% of the body and luminaire are made of recyclable aluminium.
ENERGY EFFICIENCY
Efficiency
Relative to the national power grid, the efficiency is effectively infinite – i.e. zero power taken from the grid.
The use of automatic off-peak dimming and the inherent efficiency of directed light afforded by using LED’s result in an overall energy saving of 40% compared with an equivalent metal halide solution without dimming.
Conservation
Embodied energy has been significantly reduced along with elimination of PVC, due to the avoidance of underground cabling and conduits. Similarly, avoidance of trenching negated the need for the associated removal of spoil.
The exclusive use of solar energy means that the system has zero impact on the national grid, CO2 and greenhouse gas emissions.
DARK SKY CONSIDERATIONS
The luminaires have been installed with zero upward tilt.
The IESNA ‘BUG’ rating for the luminaire is B1-U0-G1, so the Backlight (B) is well controlled and the Uplight (U) is zero. As a result, the spill light at the park boundaries close to any residential areas is zero and the optics control the light to minimise glare to observers beyond the site.
The decision was made to set back the lighting to 25% lumen output during low activity times at night. This was to minimise light pollution rather than for energy saving as the system is off-grid. However, this approach also helped to minimise the photovoltaic array and battery capacity.
The possibility of incorporating movement sensors was considered but discounted to avoid possible nuisance effects to nearby residential properties.
There is no direct light emitted above horizontal and the reflected light is minimised as the wasted spill light is less than it would be for a similar discharge lamp luminaire.
As such, the potential sky glow has been minimised as much as possible and the night sky preserved. The orange skyglow evident in the images is caused by the pre-existing sodium streetlights.
