Adding Zest to the display

The lighting design team at BDP accepted an invitation from Lighting to review Nualight’s new linear LED accent light for retail and to interrogate its designer, Dan Linehan. In a new departure for our ‘Anatomy of…’ series, Mark Ridler and Luke Smith-Wightman got their hands on the fitting

“Supermarket lighting has undergone a complete transformation in the space of five years,” observes Dan Linehan, designer at lighting manufacturer Nualight. As a result, the firm’s LED range has extended from lighting freezers and chillers to under-shelf and even canopy lighting. Now the company is set to launch its most ambitious product yet, with what Nualight claims is the world’s first linear LED accent light for fresh food displays in supermarkets.

Called Zest, the sleek-looking, modular unit with an anodised silver finish has a pivoting inner core, housing a row of uniformly spaced LED lamps to deliver an uninterrupted, sharply focused beam of light along the line of a food display. The unit is claimed to deliver up to 40 per cent energy savings, compared with conventional HID lighting, and Nualight argues that it offers better light utilisation than LED spotlights. “There are a million LED spotlights but they’ve got to be aimed at the produce, whereas, because most displays in supermarkets are linear, you just line up this luminaire,” Linehan explains. The luminaire is suitable for lighting fruit, vegetables, meat and flowers and, because the beam can be angled, it can also be used to illuminate products on vertical shelves.

Two power levels

The fitting is available in two power levels: 33W or 66W per 1.2m module. The higher-power units will be used in stores with a higher ambient lighting level; standard power is available for energy-conscious users. And, because it uses LED technology, it also has a guaranteed lifetime of 50,000 hours with a lumen maintenance of 70 per cent of the initial luminance after five years, backed up by reliability data from the LED manufacturers.

“Is it available in continuous runs?” asks BDP senior lighting designer Luke Smith-Wightman, removing one of the end-caps to scrutinise the unit’s endplate. Linehan explains that the unit is available in 1.2m or 2.4m lengths, which can be snapped together to form continuous runs without tools. “The 2.4m version speeds installation on larger schemes,” he says. In addition to selecting the unit’s length, specifiers also have the choice of two different beam angles: 42 degrees or 29 degrees. “The wider beam is generally for a 1.5-2.5m mounting height, while the narrower beam is for higher mounting from 2m to 3.5m,” says Linehan, holding the unit in the air.

Looking up at the luminaire, Mark Ridler, director of lighting at BDP, wants to know if the beam angle is symmetrical. “We looked at making it asymmetric but we thought it would be more general-purpose in a symmetrical arrangement; as a result the beam is slightly more powerful in the centre,” says Linehan.

Smith-Wightman is interested in the luminaire’s light output. There are three different colour temperature versions of the fitting: a 3,000K version, suitable for red meats and red fruits; a warmer 4,000K version for lighter-coloured meats, fruits and vegetables; and a tunable version, whose colour temperature can be set between 2,700K and 5,000K, which is also the most efficient luminaire in the range. Linehan says the tunable model “will maintain a colour rendering index (CRI) of over 90 at all colour settings”. The standard, less expensive, 3,000K and 4,000K units are less efficient, with a CRI of 85. “All models have a very sharp beam pattern so that all of the light produced ends up on the produce, which means the light is utilised more efficiently compared with a spotlight, where less than half will end up on the display,” says Linehan.

Ridler wants to know whether the luminaires are Part L compliant. “I take your point about utilisation, which is not widely understood by the powers that be; nonetheless Part L demands data in terms of luminaire lumens per Watt; how does this product perform?” he asks. According to Linehan, the 3,000K and 4,000K models meet Part L, while the colour tuning version has “a very high luminous efficacy of 70-80lm/W – which will probably beat anything else out there,” he says.

Seasonal tuning

The ability to tune a lamp’s colour temperature will give supermarkets the ability to optimise its colour to match the produce on display or to accommodate produce changes between seasons. For example, brightly coloured fruit might be displayed in summer where more subdued tones of root vegetables will be on show in the winter. “It is a desirable feature but it may not be all that well managed by the stores,” admits Linehan.

“How do you change the colour?” Smith-Wightman asks, scrutinising the fitting. There are two ways: manually, using a button on the side of the unit, or using a remote control. “The fitting cycles through the settings: 2,700K, 3,000K, 3,500K, 4,000K, 4,500K and 5,000K,” Linehan explains. There is also the option of a DALI-controlled version, which will enable the unit to be linked to occupancy sensors, cutting light levels to 20 per cent when the supermarket aisles are empty.

“Will improvements in the efficiency of LEDs be reflected in the unit’s description?” Mark Ridler wants to know. He says a lot of LED luminaire manufacturers are now specifying products in terms of lumens, rather than Watts, because of anticipated increases in LED efficiencies, which is important if you are specifying a product that won’t be purchased for another two or three years. “Is that something you think you might do in terms of describing your product or will you continue with watts per metre?” he asks.

Linehan’s response is based on his market experience: “We will principally be going down the watts-per-metre line, because our supermarket customers understand watts per metre and a lot of them are on a W/m2 budget,” is his reply.

Once the unit is suspended, the beam angle can be adjusted and aligned to cut off at the bottom of a display. Glare is controlled by three means: specular reflectors, the lower edge of the tulip-shaped LED casing, and a truncated beam along the aisle. “We’ve worked very hard on glare control,” Linehan says.

The unit is assembled from components made by various contract manufacturers in Europe and the US, but not China. It uses LEDs manufactured by Cree. According to Linehan, the cost of the luminaire will vary between about £200 and about £900 for the larger models with higher outputs. The unit will be appearing in supermarkets from January.

Have your say

You must sign in to make a comment.