Lighting Solutions White Paper

Lighting Solutions White Paper

A framework across agricultural, intelligent and industrial lighting

Queendom Lighting Solutions Group · Application Engineering

This paper describes how Queendom structures a lighting project across three application families — agricultural, intelligent and industrial — and where the engineering decisions in one family differ from the others. It is written as a framework rather than a catalogue: the reader should finish it able to place a project in the right family, name the binding constraint, and ask for the measurements that decide the outcome.

The three families share hardware and diverge sharply in what governs success. Agricultural lighting is governed by spectrum and photoperiod. Intelligent lighting is governed by the control architecture and by whether the building’s occupancy pattern can actually be modelled. Industrial lighting is governed by environmental survival. A solution that ignores the family boundary will be over-specified in one dimension and under-specified in another.

1. How the three families differ

Reading a specification against the wrong row is the most common early error. A horticultural project judged on luminous efficacy (lm/W) rather than on photosynthetic photon efficacy (µmol/J) starts from a metric that does not describe what the crop receives.

2. Agricultural lighting

2.1 Spectrum is the product

In horticultural lighting the spectral power distribution is the deliverable, not a characteristic of it. Blue photons (approximately 450–470 nm) drive vegetative expansion; red photons (approximately 630–660 nm) drive flowering and fruiting; far-red (around 730 nm) carries the phytochrome signal that governs stretch and flowering timing.

A full-spectrum luminaire is not automatically better than a red-blue one. Full spectrum is easier to audit visually, which matters where people work under it; red-blue is more photon-efficient per watt of installed load. The correct choice depends on whether the installation is judged by crop response, by human working conditions, or by both.

2.2 Photoperiod and DLI

Daily light integral (DLI) is the total photosynthetic photon flux delivered per square metre per day, in mol/m²/day. It is the quantity the crop integrates, and it combines instantaneous intensity with photoperiod. A specification that fixes illuminance but leaves photoperiod open has fixed half of the variable.

DLI is not illuminance and it is not PPFD. Illuminance (lux) is photometric and weighted to the human eye; PPFD is photosynthetic and weighted to the plant; DLI integrates PPFD over the day. Substituting one for another is a category error that survives surprisingly deep into a project.

2.3 Livestock and aquaculture

Animal housing lighting is a welfare and productivity intervention, not a photometric one. The objectives are a stable photoperiod, an even distribution at animal eye level, and a spectrum that does not produce flicker or an aversive colour cast. Where a cattle house specification applies, it typically sets illuminance at the feed face and at lying areas separately, and it constrains flicker rather than luminous efficacy.

Aquaculture lighting runs at the opposite end of the spectrum: the wavelength has to penetrate the water column, which is why blue-green coverage (450–550 nm) dominates underwater fixtures. Ingress protection is not optional and is usually the binding constraint on service life.

3. Intelligent lighting

3.1 The control architecture comes first

An intelligent installation is a control system with luminaires attached. The architecture — which device decides, what it can sense, and what happens when the network is unavailable — determines the outcome more than the fitting does.

Zoning is the decision that most often determines whether a control scheme saves energy. A zone larger than the occupancy pattern it is meant to track will simply be lit whenever any part of it is occupied, and no amount of protocol sophistication will recover the difference.

3.2 Human-facing performance

• Illuminance at the task plane, not at the ceiling.
• Flicker: percentage modulation should be low enough not to be perceptible, and this is a driver property before it is a luminaire property.
• Glare: unified glare rating is a function of luminaire luminance and geometry, and rises as ceiling height falls.
• Colour rendering: a CRI of 80 or above where colour judgement is part of the task; higher where it is the task.
• Blue-light content in the evening hours, which is a scheduling question as much as a spectrum one.

4. Industrial lighting

Industrial applications are covered in detail in the companion Industrial Lighting White Paper. The summary position, sufficient for placing a project in the framework, is that this family is governed by environmental survival and by access economics rather than by photometric finesse.

5. What the three families share

Hardware overlap across the families is real, and the shared elements are the ones that most reliably determine whether an installation is still performing in year five.

6. Worked example — choosing between two solutions

A 3,000 m² greenhouse and a 3,000 m² chilled distribution centre each require a lighting solution. Both look, at first glance, like “a retrofit”. They are not the same project and the framework separates them immediately.

The two columns are not variants of one answer. They differ in the metric that defines success, and therefore in the evidence a supplier must supply. Asking a single luminaire family to carry both projects is how a solution ends up excellent at one and marginal at the other.

7. Common mistakes across all three families

• Adopting a metric from the wrong family — luminous efficacy for a horticultural project, or PPFD for a warehouse.
• Specifying the luminaire and leaving the driver, the optics and the control logic unstated.
• Treating the photometric file as a marketing attachment rather than the design input.
• Assuming a control system compensates for poor zoning. It amplifies zoning; it does not fix it.
• Omitting the maintenance factor, or taking the factory figure for a hostile environment.
• Reading L70 life as a warranty. It is a population statistic under stated conditions.
• Designing without the commissioning measurement in mind, so that acceptance becomes a matter of opinion.

8. Specification checklist

The same eight lines apply across the three families; only the acceptable answers change.

• Application family, named explicitly, and the binding constraint that follows from it.
• Primary metric appropriate to that family, and the target value.
• Photometric or spectral distribution required, not merely an output figure.
• Environmental range: ambient temperature, humidity, corrosive class, ingress rating.
• Mounting height, spacing and the optical distribution that makes them work together.
• Control architecture, including fallback behaviour with the network unavailable.
• Maintenance factor and cleaning interval assumed in the design.
• The acceptance measurement: what is measured, at what plane, and against which threshold.

9. Conclusion

A lighting solution is well-formed when the family is named, the binding constraint is stated as a number, and the acceptance test measures that number. Where those three are present, the choice of luminaire is a short conversation. Where they are absent, the project substitutes a comparison of catalogue outputs for an engineering decision, and the substitution is usually discovered at commissioning. The three families described here share components and diverge in their definition of success; keeping that distinction visible from the first page of the specification is the whole of the method.

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Queendom · figures in this paper are typical values for the series named and are subject to the measurement conditions stated. Product commitments are made on the datasheet and in the contract, not here.