What to look out for when looking to purchase undercounter/freestanding refrigerators and freezers

To select the correct undercounter/freestanding lab refrigeration system for a small to medium-sized laboratory or healthcare facility you must evaluate a system’s capability to satisfy a number of important criteria. This post explains important criteria to consider.  

They include:

• required storage capacity
• refrigerator/freezer temperature range
• stable, accurate temperature control
• alarm systems signaling temperature excursions
• auto defrost vs. manual defrost
• compliance with standards
• other useful features

While these criteria apply to any laboratory/scientific refrigeration system, this post focuses on undercounter/freestanding refrigerators and freezers for small to medium-sized facilities.  Our examples come from the new line of Norlake White Diamond units now available from Tovatech.

Determine Optimum Storage Capacity

Lab and scientific refrigerators and freezers, as with domestic models used in your home, are available in a wide range of storage capacities. 

Two things to keep in mind about storage capacity when selecting your unit:

1. Refrigerators and freezers should not be overfilled, but
2. Full units provide better performance

When purchasing a scientific freezer or refrigerator consider the amount of product you will need to have available for a particular time period or the maximum number of samples you expect to store at any given time. 

While you certainly want a unit with sufficient storage capacity for your lab or medical practice, note that a full refrigerator or freezer does a better job of maintaining the temperature.

By the same token, when stocking your unit allow space for cold air to circulate between and among contents and avoid having containers contact interior walls. 

We suggest spending some time to carefully analyze your storage needs in terms of volume, frequency of use and replacement then select an undercounter or freestanding unit best-suited to your needs.

As you check into the White Diamond series of undercounter and freestanding units you will note that they are offered in a variety of storage capacities.

Select a Unit Delivering Correct Storage Temperatures  

Today’s scientific refrigerators and freezers such as the White Diamond series offered by Tovatech offer microprocessor temperature control allowing you to select the optimum storage temperature within precise limits. 

White Diamond undercounter/freestanding refrigerators, for example, allow you to set temperature in Fahrenheit at 36? to 46? or in Centigrade 1? to 10?.  The freezer units can be set to +5 to -13? F or -15 to -25? C .   

Correct storage temperatures are usually recommended by pharmaceutical manufacturers or professional association recommendations.

Stable, Accurate Temperature Control

Unlike your household fridge as well as many commercial units that set temperatures with the twist of a dial offering choices such as cold, colder, coldest and off, scientific units such as the White Diamond series feature microprocessor temperature control. 

This allows you to set precise temperatures and provides a digital display of not only internal unit temperatures but also the temperature of contents in the units.

To explain, the display of the internal temperatures in these units is accomplished by two internal probes.  One is in air for the cabinet temperature, one is in a glycol bottle to represent content temperature.  (These units also have an external port allowing users to insert an additional probe.)   

Microprocessor temperature control responds quickly to internal temperature fluctuations when doors are open to stock or retrieve contents.

Alarm Systems Signaling Temperature Excursions

A refrigerator or freezer door left open too long, or one that does not completely shut, as well as a circuit outage can quickly allow internal temperatures to rise above set limits. 

Unit malfunctions could also result in temperature increases or decreases.

That’s why the White Diamond scientific refrigerators and freezers are equipped with audible and visual high/low temperature alarms. 

Units are also equipped with remote alarm contacts to alert personnel elsewhere in the facility to temperature excursions.

Auto Defrost vs. Manual Defrost

Most simply put, auto defrost units can be classified as low maintenance (the units do the work) while manual defrost means precise control of the defrosting cycle at your instigation. The Norlake White Diamond series of refrigerators and freezers are available in manual or auto-defrost options.

Auto-defrost scientific refrigerators are generally favored by laboratories and pharmacies.  Most models have fans that circulate chilled air throughout the unit.  This has the advantage of creating a uniform internal temperature. 

A manual-defrost scientific refrigerator cools by circulating refrigerant through tubing in the walls.  The internal temperature differential causes the cold air to circulate.

Because there is no fan-forced air circulation in manual-defrost refrigerators they are favored for applications such as experiments in open containers where it is not permissible for product to dry out due to moving air.

Manual defrost refrigerators are maintained by wiping down the interior walls every few days to remove condensed moisture.

Auto-defrost scientific freezers are preferred by most labs for convenience.  They are self-maintaining and don’t require the availability of a second freezer during defrost cycles.  These freezers use a heater to defrost the evaporator coils, which causes a small temperature spike within the unit. This can be minimized by keeping the freezer compartment full, whether with product or with ice packs. 

Manual-defrost scientific freezers work on the same principal as manual-defrost refrigerators.   But in this case ice buildup on interior walls and on the condenser must be removed on a planned basis that includes providing alternative freezer space for the contents during the defrosting operations. 

Compliance with Standards

Standards may come into play when selecting scientific refrigerators and freezers.  Certain White Diamond undercounter/freestanding units are available to meet selected standards.  Among these are:

• Meeting CDC guidelines for vaccine storage. This always critical and especially so for organizations participating in the Vaccines for Children program.
• ADA Compliance.
• NFPA Compliance for storage of flammable materials. A White Diamond freezer and refrigerator meet NFPA requirements 45 and 70 for storage of flammable contents.

Other Useful Features

The Nor-Lake White Diamond units featured in this post are offered in two basic configurations.

1. Built-in undercounter refrigerators and freezers are designed to be inserted into existing or new cabinetry and have a front-breathing ventilation system that allows a tight fit. These units are also finished on the tops and sides, making them attractive as stand-alones.
2. Freestanding/undercounter refrigerators and freezers, some models of which can be used as countertop units, can be inserted into cabinetry but require a 4″ clearance at the top and sides for air circulation.

With the exception of the ADA-compliant unit all models can be ordered with the optional left-hinge door. 

All units have a keyed door lock, are extremely power efficient, feature magnetic door gaskets for a positive seal, are fitted with leveling legs for perfect positioning and offer shelving options depending on model.

A three-year parts and labor warranty protects your investment.

more on the Norlake White Diamond range