A Comprehensive Guide to Frozen Cold Storage

For over 50 years, retail marketing of frozen foods has been growing by leaps and bounds. This trend can be attributed to the convenience these foods offer, their availability throughout the year, and the high quality of the products. The quality of frozen foods, however, primarily depends on the manufacturing process, raw materials used, and the maintenance of low temperatures during storage, transportation, distribution, and retail display. Failure to maintain the desired temperatures throughout the cold chain can affect the quality of frozen foods and, thus, customer satisfaction. 

Here, effective frozen cold storage plays a critical role. Let us delve into the role of frozen cold structure, its benefits, management, construction, and much more. 

Understanding Cold Storage Rooms

Cold storage is a specialized room wherein the temperature is kept very low with the help of machines and precision instruments. Cold storage facilities can be considered the primary infrastructural component for perishable commodities such as fruits, vegetables, seafood, meat, dairy, etc. 

They are essential for extending the shelf-life of the products, maintaining the quality, and delaying and avoiding deterioration. From the perspective of farmers, traders, and consumers, cold storage helps avoid glut, stabilize market prices, and evenly distribute prices both on the demand basis and time basis. Thus, cold storage rooms play a key role in reducing the wastage of perishable commodities. 

With that being said, cold storage facilities also need to overcome potential operational issues such as preserving end-to-end cold chain integrity, minimising energy costs, and ensuring product traceability. 

Exploring Frozen Cold Storage

Frozen cold storage, also known as a frozen warehouse, refers to specialized storage facilities designed to maintain a consistently low temperature (usually sub-zero) for the storage of frozen food products. These facilities play a key role in preserving the quality and safety of frozen foods throughout the supply chain.

Frozen cold rooms are designed to maintain temperatures typically ranging from -18 ℃ (0 ℉) to as low as -30 ℃ (-22 ℉). Moreover, relative humidity is kept at the highest possible which is consistent with available equipment and good operating procedures. This is done to avoid “freezer burn” and drying out in case the food packaging material may not have good protective capability.

Storage Period  

As temperatures become colder, storage life or shelf life can be extended significantly. For most products, if the storage period is expected to be more than six months, a temperature of -18 °C  (0 °F ) or below is required. However, the relative stability of a variety of frozen foods at 0 °F may vary. Here’s a quick look. 

Image source: Frozen Foods Handling & Storage 

Time & Temperature Tolerance (TTT)

The combined effect of temperature and time on frozen foods can impact the colour, flavour, texture, and ultimately, quality. The degree to which products can tolerate the effects of time and temperature is called Time-Temperature Tolerance (TTT). Food regulations or a company’s quality standards must determine and control both time and temperature factors to ensure product quality. 

Image source: Frozen Foods Handling & Storage

Comparing Cold Storage and Frozen Cold Storage

Here are some prime differences between cold storage and frozen cold storage. 

• Temperature Range 

Cold storage rooms maintain temperatures from around 0 ℃ (32 °F) to 15 ℃. This range is suitable for storing perishable commodities and produce that require low temperatures (cooling) but not freezing conditions. 

Whereas, for frozen cold storage facilities, on the other hand, the temperature ranges from  -18  ℃ (0 °F) to as low as -30 ℃ (-22 °F). Very low temperatures are required for long-term storage of frozen food products and pharmaceutical items. 

• Commodity Type

Cold storage facilities are specially designed for extending the shelf life of perishable products that do not require freezing. Some examples include dairy products, bakery items, fresh produce (fruits and vegetables), processed food, dairy products, seafood, meat, etc. 

Frozen cold storage is used for storing and preserving frozen commodities such as frozen vegetables and fruits, frozen meats, ice cream, pre-cooked meals, frozen desserts, etc.

Management of Frozen Storage

Managing a frozen cold storage warehouse requires attention to quality, safety, operations, and more. Here are some aspects you need to focus on. 

Temperature Control and Tracking

It is important to implement an effective temperature monitoring system with sensors that should be placed strategically throughout the facility. Make sure to calibrate your refrigeration system to ensure they are operating at the desired temperature. 

Storage Optimisation

You should optimize the storage space in frozen warehouses by utilising shelving and racking systems along with proper labelling. This will ensure effective inventory management by facilitating the first-in, first-out (FIFO) system for stock rotation and reduced spoilage. 

Efficient Workflow and Layout

The layout of the frozen cold storage facility should enable smooth and efficient movement of products, personnel, and equipment. Make sure there is a minimum distance travelled between different areas and the pathways are clear to avoid any delays. 

Cleaning and Sanitation

A high standard of cleanliness and sanitation should be a priority within the facility. Make sure the protocols in place are clear and prevent any accumulation of debris, dust, or contaminants. These practices will ensure the safety and quality of your commodities. 

Employee safety and training 

Provide thorough training to the employees working at the frozen storage. They should be familiarised with the right protocols for handling, storage, and safety of frozen products, Moreover, they should have knowledge of the use of the equipment and machinery as well as PPE (personal protective equipment) to maintain their safety as well. 

Security 

Make sure security measures including, access to control systems, alarms for any temperature fluctuations, and surveillance cameras are in place for the safety of the facility as well as its contents. 

Disaster Management 

Develop and implement a robust disaster preparedness and management plan. This may include a response to potential natural disasters, power outages, equipment failures, or other emergencies. You should have contingency measures in place with power back and a clear communication plan. 

Maintenance and Inspections

Regular or routine inspections or maintenance checks are necessary for your construction and equipment (refrigeration system, etc.). This will enable longer service life by addressing any imminent issues, repairs, or malfunctions. 

Regulatory Compliance 

You need to stay updated on relevant guidelines and regulations related to frozen food storage, handling, and safety. Make sure you maintain proper documentation, safety standards, and hygiene practices. 

Designing a Frozen Food Storage Warehouse

When planning a frozen food storage warehouse, several elements and factors come into play. 

Size and Space

Plan based on your expectations in the next 10 to 15 years. Consider the amount of product/commodity you would store and the associated cost. Here, it will be important to consider the ROI (return on investment)that you can achieve from the completely constructed cold storage warehouse. 

Choose an appropriate size considering how the product will be stored (pellets, bins, aisles, shelving systems, etc.), how you will access it, whether you will have different rooms, where will your refrigeration system be placed, whether you will expand the storage facility in the future, etc. 

Food Quality 

When designing the facility, make sure quality during processes such as processing, packaging, and shipping is maintained. Here location will also be critical. The cold storage warehouse should be near transportation lines. However, this may result in increased costs. 

Energy Consumption

Consider energy costs associated with cold storage warehouses. You can reduce your energy bills by using energy-efficient LED lighting and refrigeration systems, considering the temperature difference of adjacent rooms, insulation, etc. 

Refrigeration System 

Usually, a refrigeration system comprises a condenser, compressor, evaporator, and refrigerant. Make sure they are compatible and efficient to maintain very low (freezing) temperatures. Automation in refrigeration controls can also improve energy consumption by providing real-time data to make changes in a timely manner, ensuring all systems are working at maximum efficiency levels. 

Electrical Utilities 

Power outages can have implications for your cold storage facility. Therefore, electrical elements are important in design considerations. Take into account operating voltage, supply fluctuation, power backup, suitable location of electric rooms, etc. 

Insulation and Roofing

Frozen food storage warehouses must have proper insulation to maintain desired temperatures with minimal energy bills. Floors, roofs, and walls should be of adequate thickness and coated with reflective material. Sandwich insulated panels (SIPs) that have a high R-value offer high resistance against heat transmission. For instance, PUF (polyurethane foam) panels find extensive usage in the construction of cold storage because of their excellent thermal insulation properties. 

A few key properties of an insulating material used in frozen cold storage include low thermal conductivity, high structural strength, lightweight, water-repelling, odourless, non-inflammable, low cost, etc. 

Vapour Barriers 

Vapour barriers are the materials that are placed on the hot side of the cold storage to prevent moisture transfer and to protect the insulation from moisture condensation. Examples of vapour barriers include structural sheets of Aluminum and stainless steel, thin aluminium foils, plastic film hot melt type bitumen, special types of paints etc. 

Flooring

Usually, polyurethane (PU) concrete floorings are used in cold storage warehouses. The floors should be able to withstand freezing temperatures, tolerate heavy loads and equipment, resistant to acids and chemicals, easy to clean and hygienic, slip-resistant, and abrasion-resistant. 

Lighting and Safety

Consider energy-efficient lighting that works well in cold conditions. Also, safety measures like internal door releases and alarm systems should be incorporated into the design.

Air Circulation/ Airflow

The design should allow for good air circulation to maintain a uniform temperature throughout the room. This may involve the use of fans or specific placement of the evaporator unit.

Pallet Jack & Fork Lift

A forklift needs to be provided for the movement of palletized crates. High-reach stackers or pallet jacks are needed depending on the height of palletization.

Dock

It is recommended that the loading and unloading dock be designed with an RCC slab roof or sheet roofing. However, the machine roof can have an RCC slab roof to accommodate the evaporative condensers, pump sets, water tank, water softener etc.

Entry and Exit Points

Freezer warehouses typically have a cooled room designed for product quality control during goods receipt and dispatch. A key feature of these systems is a secure airlock system involving two interlocking doors – one linking to the freezer warehouse, the other leading outside. These doors never open simultaneously, helping to prevent abrupt temperature fluctuations, loss of cold, and condensation, thereby avoiding ice build-up.

Equipment and Hardware in Frozen Storage Facilities

A freezer warehouse has both automated and non-automated systems. 

Non-Automated Storage Systems 

In non-automated or traditional freezer warehouses, operators use forklifts to manually handle goods within the storage systems. These facilities can accommodate various storage systems like pallet racking, with compact systems such as drive-in pallet racking, live pallet racking, and push-back pallet racking being the most popular due to their efficient use of space.

Mobile pallet racking is another system that fits in this category. It’s a high-density system that optimizes air distribution among a larger number of stored pallets, significantly reducing the energy needed to maintain a controlled temperature in the warehouse.

Automated Storage Systems 

Automated systems, on the other hand, significantly enhance operations in freezer warehouses by mitigating the negative impacts of freezing temperatures on staff productivity. Automated Storage and Retrieval Systems (AS/RS) are particularly effective for maximizing available space and ensuring safe, controlled goods movements.

AS/RS in freezer warehouses can comprise single- or double-deep pallet racking. A stacker crane automatically manages the goods in these systems. Single-deep racks offer direct access to the pallets and are preferred when such access is required, while double-deep racks increase storage capacity. Moreover, for larger storage needs, the automated pallet shuttle system is a great alternative. This system includes racks with deep channels, similar to those in non-automated systems, which facilitate the automatic insertion or removal of goods using a motorized shuttle. 

Final Words 

Undoubtedly, a freezer warehouse is a critical part of cold chain operations across various industries including food, pharmaceuticals, seafood processing, and others. A frozen cold storage can prove a game changer for your business because it can not only meet your storage or capacity needs but also optimise energy consumption. 

To know more about effective solutions for your cold chain needs, get in touch with Rinac’s team today!