LED lighting design considerations for Freezer’s

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LED lighting design considerations for Freezer’s

LED’s are being used for a wide variety of applications due to the many advantages they provide over other forms of lighting technology. Most modern freezers and refrigerators now use LED lighting system’s which can withstand the typical freezing and below freezing environment. 

This industry can be broadly classified into 3 different sectors:

·       Home

·       Commercial

·       Industrial

Home Applications: The kitchen refrigerator and home freezers are now being fitted with LED lights that are designed to provide better aesthetics with low heat. The latest trends feature ‘cool-white’ light with timed dimming capabilities.

Commercial Applications: Typical applications in this sector include walk in/reach in type freezers, most super-markets have now transitioned into using LED’s with high CRI’s to enhance the look of the displayed products. Efficiency of power used and the longevity of the system are deciding factors for this system.

Industrial Applications: Many cold storage, and warehouses that store perishable foods and industrial parts at low temperatures, now employ high power LED fixtures. The lumen output is the critical factor as the amount of light needed to perform work in these environments can vary from low to day-light bright.

Different types of LED’s and LED drivers are used to tackle the different needs of the freezer industry, where the temperature ranges can vary from -25˚C to +4˚C, with varying humidity levels. The LED’s ON times can also vary from being used less than an hour a week to being ON constantly. Lighting in this controlled environment can also experience extreme fluctuations, especially during power outages and critical component failures (e.g. compressor failure). A robust LED lighting system must be able to perform well under all these conditions.

A Design Engineer persevering to find ideal solutions to these challenges must address the following selection factors:

  1. Type of LED casing: Depending on the application, one must choose the appropriate LED shape and casing. Strip LED’s, recessed panel’s, individual COB’s, or even high power pre-fabricated fixtures. A designer must also calculate the beam angle and lumen output for selecting the perfect location to place the fixtures. 
  2. Color Performance: The CRI (Color Rendering Index) which dictates the wide range of colors viewable in the light is extremely important in application such as reach in freezers that present colorful products to the customers. The color temperature of the LED light describes how the light appears when an illuminate bulb is viewed directly by the human eye. It is measured in degree Kelvin (K). They can range from 2700K which is a yellowish warm light to 6500K which is very white or cooler light. Most freezer and refrigerator lights now utilize cooler lights.
  3. Efficacy and light output: Efficacy is a measure of how efficient a bulb is in converting electricity (measured in watts) to light (measured in lumens). Design Engineers need to meet the minimum required lumens for their target applications while maintaining high efficacy and the low total power consumption.
  4. Controllability: The LED’s can be sensor controlled or have dimming functionality or both. This requirement adds an additional layer of complexity and cost to the overall project.
  5. Life time cost: Another consideration is how much a lighting source costs to purchase and operate over the course of a system’s lifetime.

 

Once the above design considerations are evaluated, the selection of the right type of LED driver is crucial to ensure the system performs as intended. The vital criteria for selecting a good LED driver include the following:

OCP: Over current protection defends against excessive current being consumed by the LED’s which can result in premature failures or reduction of lumen output.

OVP: Over voltage protection defends against the overvoltage conditions that occur during load-dump events or transients.

SCP: Short circuit protection safe guards against dangerous inrush of current during shorts. Most electrical fires are caused due to shorting.

Derating Curve: This curve shows the effective range of conditions that the driver will perform as designed. A good driver’s performance should not decrease for all the entire temperature range requirements of the application. Another important factor for freezer applications is the ability of the driver to cold start (turning on the driver at low temperatures).

Plotting: Plotting provides ingress protection from dust and water and helps the thermal conductivity of the driver indirectly increasing its life by reducing the thermal stress.

Efficacy: The efficiency of the driver is extremely important to the overall efficiency of the system.

Output current, voltage and power: Together they determine the amount and type of LED’s that can be paired with the selected drivers.

Standards: Most markets now have regulations concerning the design of the LED drivers, the selected driver must be able to meet the required governmental standards.

PFC: Power factor correction helps in making the system more efficient.

While switching to LED’s the Industry looks towards:

  1. Actual energy savings
  2. Increased customer satisfaction/experience
  3. Moderate costs
  4. The system to work problem free and have very low maintenance
  5. Enhanced quality of light
  6. Conformity to Standards

 

Such harsh requirements mandate that an LED driver can not only survive these extreme cold conditions for the life of the LED, but also provide a consistent output for the LED’s to perform in their designed optimum output ranges. Aimtec’s advanced LED drivers provide options for both AC and DC input’s with a wide range of output current, voltage and power options. All Aimtec’s AC-DC LED drivers offer OCP, OVP SCP and PFC, and many of Aimtec’s AC-DC LED Driver series offer a wide input range from 90~305VAC. All the drivers are highly efficient with DC-DC LED Driver line offering up to 96% efficiency. Aimtec’s LED Driver product line offers a wide range of environmental protection from dust and water up to a rating of IP68. Amitec’s LED drivers are designed and tested to be long lasting, reliable and conforming to various safety and EMC standards including UL 60950-1, UL 8750 and EN55015, and are offered with industry leading warranty.