Bristol Cold Storage LED High Bay Lighting Project | XHLWX

Introduction — the On-site Problem

com), a Custom Indoor LED Lighting Manufacturer based in China, we specialize in developing solutions for challenging industrial environments. For a new-build, large-scale cold storage and logistics facility in Bristol, United Kingdom, the primary challenge was designing a lighting system capable of performing reliably and efficiently in a constant ambient temperature of -30°C.

Standard luminaires face significant risks in such conditions, including material embrittlement, driver failure, and inconsistent light output. The client required a robust, high-performance LED lighting system that would ensure safety, minimize energy consumption, and virtually eliminate maintenance over its long operational life.

What "custom" Meant on This Project — Capability Matrix

The project demanded a luminaire engineered from the ground up for extreme cold. We developed a bespoke IP66 linear high bay tailored to the client's operational requirements.

The design focused on material selection, thermal management, and optical performance specific to high-rack warehousing. The target specifications for our custom XHLWX-CSLHB-150W luminaire are detailed below.

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Engineering Solutions

How Were the Luminaires Designed for -30°C Operation and Freeze-thaw Cycles?

Our engineering approach centered on component-level resilience. We specified Tridonic drivers with a certified operating range down to -40°C, ensuring a stable power supply.

The luminaire housing is a fully sealed IP66 unit, using silicone gaskets that remain flexible at low temperatures to prevent moisture ingress during potential defrost cycles or cleaning. The primary housing is extruded aluminum for optimal heat dissipation away from the LED board, while the lens is a specialized low-temperature polycarbonate that resists embrittlement and impact, a common failure point for standard plastics in deep-freeze environments.

What Strategy Was Used to Achieve Uniform Illumination Between Tall Racking Aisles?

Uniformity was critical for both safety and operational efficiency, particularly for reading labels on high racks. Instead of a standard wide beam, we engineered custom optics with an asymmetric batwing distribution.

This optical design directs light laterally down the aisle and vertically up the rack faces, rather than wasting it on the tops of racks or creating hotspots on the floor.6 in the aisles.

How Does the DALI-2 Control System Reduce Energy Consumption?

The DALI-2 control system is the core of the project's energy efficiency strategy. It moves beyond simple on/off switching to intelligent, granular control.

Each luminaire is individually addressable and paired with zonal PIR motion sensors. In an empty aisle, the lights dim to a 10% baseline level.

Upon entry by a person or forklift, they ramp up to 100% instantly and then fade down after a set period of inactivity. This presence detection alone was projected to reduce lighting energy consumption by over 60% compared to a non-controlled system.

The DALI-2 network also allows for daylight harvesting near loading bay doors and provides the facility manager with real-time energy monitoring and diagnostic feedback for each luminaire.

Project Results — Design Targets

As this is a new-build project for 2026, all results are based on comprehensive design simulations and engineering targets. The solution was designed to deliver quantifiable outcomes:

• Energy Efficiency: A target system efficacy exceeding 160 lm/W, combined with DALI-2 controls, is projected to deliver energy savings of over 70% compared to a baseline using traditional 400W metal halide fixtures.
• Illuminance Compliance: DIALux simulations confirmed the design achieves and exceeds CIBSE and EN 12464-1 guidelines, with an average of 250 lux in open areas and over 300 lux on vertical rack faces for clear barcode scanning.
• Visual Comfort: The custom batwing optics were designed to achieve a Unified Glare Rating (UGR) of <22, ensuring visual comfort for forklift operators and staff working in the aisles.
• Longevity & Maintenance: A targeted L90B10 lifetime of over 80,000 hours at the -30°C operating temperature means the system is designed to run for over 9 years in a 24/7 operation before its output degrades to 90% of initial brightness. This effectively eliminates the need for routine lighting maintenance.

Photometric Files & Compliance (IES / LDT / DIALux / CE / RoHS)

Full transparency and design validation are cornerstones of our process. For the Bristol facility, XHLWX provided a complete documentation package.

This includes standardized IES and LDT photometric files for the custom XHLWX-CSLHB-150W luminaire, allowing for independent verification of the lighting plan. The client and their engineering consultants were also supplied with a comprehensive DIALux EVO project file, detailing every calculation, from illuminance levels to glare ratings.

All supplied components are fully certified and compliant with CE (European Conformity), UKCA (UK Conformity Assessed), and RoHS (Restriction of Hazardous Substances) directives.

Frequently Asked Questions

Q: How Low Can the Temperature Be for These Specific Luminaires?

The custom linear high bay luminaires developed for this project are engineered for a continuous operating temperature range of -40°C to +50°C. This specification provides a significant safety margin for the facility's target ambient temperature of -30°C, ensuring consistent performance, light output, and long-term driver reliability.

Q: Why Was a CRI of Over 80 Specified for a Storage Area?

A Colour Rendering Index (CRI) of >80 Ra is essential for operational accuracy and safety. In a busy logistics environment, this level of color rendering ensures that warning labels, branding colors on packages, and other visual indicators can be identified quickly and correctly. It reduces picking errors and enhances the overall visual comfort for staff.

Q: What Makes the DALI-2 Control System Superior to a Standard Sensor?

The DALI-2 system provides digital, addressable control over every single luminaire. Unlike a simple standalone sensor controlling a bank of lights, DALI-2 allows for precise dimming schedules, individual aisle-by-aisle presence detection, and energy monitoring. The system can report lamp and driver failures for over 450 luminaires, streamlining maintenance and ensuring system integrity.

Q: What Is the Warranty Provided for a Custom Fixture in Such a Harsh Environment?

XHLWX provides a comprehensive 5-year, full-performance warranty on the entire luminaire, including the Bridgelux LED modules and the Tridonic driver. This warranty is fully applicable to the specified -30°C operating environment, offering the client complete assurance in the long-term reliability and durability of our custom-engineered solution.

Sources and Technical References

1. BS EN 12464-1:2021: Light and lighting — Lighting of work places — Part 1: Indoor work places.
2. CIBSE Lighting Guide 01 (LG01): The Industrial Environment.
3. IEC 62722-2-1: Luminaire performance - Part 2-1: Particular requirements for LED luminaires.
4. DiiA Specification DALI Part 102: General Requirements for Control Gear (DALI-2), The DALI Alliance (dali-alliance.org).

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com), a Custom Indoor LED Lighting Manufacturer based in China, we thrive on solving complex lighting challenges for our partners in the EU, US, and Middle East. This Bristol cold storage project demonstrates our capability to engineer high-performance, reliable luminaires for the most demanding industrial applications. If your project requires a lighting solution that goes beyond off-the-shelf products, contact our engineering team to discuss your requirements and begin the design process.