Walkin-Cooler

Factors Impacting Walk-in Coolers & Freezers' Lifespan

There are numerous factors that contribute to the longevity of a walk-in cooler or freezer. These range from how often the door is opened to environmental stressors. Here are a few key considerations:

• Usage Frequency:

  Frequent door openings in a busy restaurant, grocery store, or warehouse can lead to increased wear and tear, not only on the door seals but also on the refrigeration system. The more the door is opened, the harder the system has to work to maintain the desired temperature, putting additional stress on the compressor and other components. Over time, this can shorten the unit's lifespan. For units used in high-traffic areas, considering repair and preventive maintenance earlier in the lifecycle might be wise to avoid breakdowns.

• Environmental Factors:

  The environment where the walk-in cooler or freezer is installed also plays a significant role in determining its lifespan. Indoor units, although protected from rain and snow, can still suffer if they are exposed to high indoor temperatures, excessive humidity, or poor ventilation, which can make the unit work harder. On the other hand, outdoor units face exposure to the elements, including rain, snow, UV rays, wind-blown debris, and hail. Over time, rust can form on exposed metal parts, particularly in regions with high humidity or salty air coastal areas. Weather extremes can cause units to cycle on and off more frequently, which may eventually lead to compressor failure or reduced efficiency.

• Operational Behavior:

  Walk-in coolers and freezers are used to store a variety of perishable items, and the nature of what you store can influence the wear on your system. Storing uncovered acidic items such as cut tomatoes, citrus fruits, or vinegar can cause the evaporator coils to deteriorate more rapidly due to their corrosive nature. Salty foods, such as olives, pickles, cold cuts, and other brined or cured products, can have a surprisingly corrosive effect on copper pipes in evaporators over time, primarily through a process called galvanic corrosion. To extend the life of the evaporator and other components, ensure that highly acidic items are stored in sealed containers to limit their exposure to the internal cooling environment.

• Brand and Model:

  Not all refrigeration units are created equal, and the brand and model you select will also impact your cooler's lifespan. Certain brands are known for durability, efficiency, and build quality. Leading manufacturers such as KeepRite, Russell, and Heatcraft offer systems that share common components but differ in the quality of protective features. For instance, some models come equipped with low-pressure switches, anti-short cycling time delays, and other features that help reduce wear on the compressor, which can ultimately extend the life of the entire system.

• Maintenance & Care:

  Regular maintenance is perhaps the most critical factor when it comes to extending the life of your walk-in cooler or freezer. Preventative maintenance, including checking refrigerant levels, cleaning evaporator and condenser coils, replacing worn door gaskets, and inspecting electrical components, can help catch small issues before they become larger, more costly problems. As the saying goes, “Neglecting maintenance is a sure recipe for disaster.” — ZD. A walk-in cooler that is well-maintained can last between 10 to 15 years, and in some cases, more than 30 years.

When Is Replacement the Better Option?

While repairs can keep your walk-in cooler functioning for many years, there are situations where replacement may be the smarter, long-term choice. Here’s when you might want to consider a full replacement:

• Frequent Breakdowns:

  If your cooler is constantly breaking down and requiring frequent repairs, it may be more economical to invest in a new unit rather than continuing to pay for repairs. Constant breakdowns are often a sign that multiple components are reaching the end of their lifespan, and continuing to patch up one problem after another can be more expensive in the long run.

• Rising Energy Costs:

  Older models are typically less energy-efficient than newer ones. If your energy bills are increasing even though usage remains the same, it may be a sign that your refrigeration system is no longer running efficiently. Modern units are designed with energy efficiency in mind, and upgrading to a newer model can result in significant savings on your utility bills over time, eventually offsetting the cost of the replacement.

• Refrigerant Issues:

  Many older systems use refrigerants like R-22, which have been phased out due to environmental regulations. As a result, recharging these systems with refrigerant is becoming increasingly expensive and unsustainable. Newer units use more eco-friendly refrigerants, which are easier to source and will save you money in the long term. This might make replacement more cost-effective than continued refrigerant top-offs or retrofitting.

• Age of the System:

  If your walk-in cooler or freezer is more than 15 years old, it’s likely nearing the end of its life, especially if it hasn’t been maintained regularly. Rather than waiting for a catastrophic failure, preemptively replacing the unit can prevent downtime and lost inventory.

Evaporator Galvanic Effect

1. Formation of Electrolytic Environment

   Salty foods contain a high concentration of sodium chloride (NaCl) or other salts, which are excellent electrolytes when dissolved in moisture. When salty foods are stored in a walk-in cooler or freezer, vapors or brine residues may enter the atmosphere of the cold storage room. In some cases, even tiny droplets from condensation within the space can carry the salts.

   Copper pipes are naturally reactive with electrolytes such as salt. If there’s any moisture (from condensation or from high-humidity environments inside the cooler), the salt dissolves into it and creates a conductive solution. This forms an electrolytic environment on the surface of the copper pipes. Even the smallest amounts of salty residue can initiate this process.

2. Galvanic Corrosion of Copper

   When the salty water or residue comes into contact with the copper pipes, an electrochemical reaction occurs. This reaction is known as galvanic corrosion or pitting corrosion.

   Galvanic corrosion happens when two dissimilar metals (in this case, copper and other materials) come into contact with an electrolyte (the saltwater).

   Pitting corrosion, a more localized form, leads to the formation of small pits or holes on the surface of the copper. Over time, these small pits can penetrate the copper pipe, causing leaks and damage.

   The corrosion occurs because the saltwater acts as a bridge, allowing electrical current to flow between different points on the copper surface, leading to the gradual breakdown of the metal.

3. Accelerated Deterioration

   Once corrosion starts, it spreads quickly. Over time, the copper pipes become weakened as the surface material begins to flake away and thin. This process can also create microscopic pores or cracks, which further expose the interior of the pipes to moisture and continue the corrosion process.

   Temperature fluctuations inside the evaporator unit can exacerbate the issue. For example, in a walk-in cooler, the temperature may fluctuate slightly as the compressor cycles on and off, and any moisture from salty products can repeatedly condense and evaporate, increasing the risk of corrosion.

4. Impact on the Evaporator and Refrigeration System
   • Leaks: As the copper tubing inside the evaporator becomes pitted and weakened, it may develop leaks. Leaks in the refrigerant system can lead to the loss of cooling capacity, inefficiency, and ultimately system failure.
   • Reduced Lifespan: The overall durability of the evaporator is compromised, leading to more frequent repairs or premature replacement of the entire unit.
   • Efficiency Loss: Corrosion also reduces heat transfer efficiency. Evaporators rely on clean, conductive copper surfaces to effectively transfer heat from the air to the refrigerant. Corrosion impedes this process, making the system work harder and increasing energy consumption.
   • Compressor Stress: As the evaporator’s efficiency decreases, the compressor has to work harder to maintain the desired temperature. This added strain can lead to compressor wear and eventual failure.
5. Preventing Corrosion from Salty Foods

   There are several ways to minimize or prevent the corrosive effects of salty foods in refrigeration systems:

   • Proper Storage: Store salty or brined foods (like olives, pickles, cold cuts, and seafood) in sealed, airtight containers. This will prevent vapors or moisture from carrying the salts into the cooler’s environment, where they can condense onto evaporator coils or copper pipes.
   • Regular Maintenance: Frequent cleaning and maintenance of the evaporator coils and copper pipes are crucial. Periodically cleaning the coils with a neutral or alkaline cleaner can remove residues before they have a chance to cause corrosion. Be careful with harsh chemicals that could exacerbate the corrosion.
   • Anti-Corrosion Coatings: Some modern refrigeration systems are equipped with evaporator coils that have a protective anti-corrosion coating. These coatings form a barrier between the copper pipes and any corrosive elements in the environment, such as salts or acids from certain foods.
   • Drainage and Moisture Control: Ensure the walk-in cooler is well-drained to prevent standing water or excessive condensation, which can exacerbate corrosion issues. Maintaining the right humidity levels within the cooler can also help minimize condensation and salt buildup.

Effect of Acidic Foods on Evaporator Coils and Copper Pipes

1. Acidic Environment Formation

   Many foods such as cut tomatoes, onions, citrus fruits, and vinegar-based items release acids into the air when stored in walk-in coolers or freezers. These foods often have a low pH, meaning they contain a higher concentration of hydrogen ions, which makes them acidic.

   When acidic vapors are released into the atmosphere of the cold storage room, they can combine with condensation or moisture inside the cooler. The acids can settle on the surface of copper pipes and evaporator coils, forming a mildly corrosive solution. Even small amounts of acidic vapor can be enough to initiate corrosion.

2. Corrosive Reactions on Copper Surfaces

   Copper is highly reactive with acidic solutions. When acidic substances come into contact with copper pipes or evaporator coils, a chemical reaction occurs. This process is known as acidic corrosion.

   The acids gradually dissolve the copper surface, leading to the formation of copper salts. This process not only deteriorates the copper itself but can also leave behind residues that may further affect the performance of the refrigeration system.

   As the acidic corrosion progresses, it weakens the structural integrity of the copper, increasing the likelihood of leaks and damage over time.

3. Acceleration of Corrosion and Pitting

   Corrosion caused by acidic foods tends to accelerate, particularly in environments with fluctuating temperatures. The acids may repeatedly condense onto the copper pipes during the compressor’s on-and-off cycles, causing cyclical corrosion.

   As with salty foods, the corrosion from acids can cause pitting corrosion—the formation of small pits or cavities on the copper surface. These pits can expand and penetrate deeper into the copper, causing leaks in the refrigerant system or the need for replacement of the piping and coils.

4. Impact on the Evaporator and Refrigeration System
   • System Leaks: The acidic corrosion can lead to the formation of leaks in the copper piping or evaporator coils, allowing refrigerant to escape. This reduces the cooling capacity and leads to inefficiency, higher energy costs, and potential system failure.
   • Reduced Lifespan: Copper pipes exposed to acidic environments have a significantly shorter lifespan, necessitating more frequent repairs or replacements of the evaporator unit.
   • Heat Transfer Issues: Corrosion affects the ability of the evaporator coils to efficiently transfer heat. Acidic residues or corrosion build-up on the coils reduce the surface area available for heat transfer, leading to reduced cooling efficiency.
   • Increased Strain on Compressor: As the efficiency of the evaporator decreases, the refrigeration system must work harder to maintain the desired temperature, putting additional strain on the compressor. Over time, this strain may lead to premature compressor failure.
5. Preventing Corrosion from Acidic Foods

   To prevent or minimize the corrosive effects of acidic foods on refrigeration systems, consider the following measures:

   • Proper Storage: Always store acidic foods such as tomatoes, onions, and citrus fruits in tightly sealed containers. This prevents the release of acidic vapors into the air, reducing the risk of corrosive damage to evaporator coils and copper pipes.
   • Regular Maintenance: Clean evaporator coils and copper pipes regularly using non-corrosive, neutral cleaners. Ensure that any acidic residues or vapors are removed before they can cause damage. Avoid using strong acidic or abrasive cleaning agents, which may worsen corrosion.
   • Coating and Protection: Modern refrigeration systems can be equipped with special anti-corrosion coatings on the evaporator coils, providing a protective layer between the copper and acidic vapors. This can significantly extend the lifespan of the evaporator unit.
   • Drainage and Ventilation: Ensure proper drainage inside the cooler to prevent the accumulation of moisture, which can exacerbate the corrosive effects of acidic vapors. Adequate ventilation is also important for minimizing the buildup of acidic gases.
   • Humidity Control: Maintaining the correct humidity levels within the walk-in cooler can reduce the amount of condensation forming on the evaporator coils and copper pipes, helping to prevent acid from settling and corroding the metal surfaces.