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11/02/2021

Four Best Practices for C-store Cold Storage Applications

Operators can take simple steps to ensure their equipment operates efficiently for the long-term.
C-store Cold Storage

Convenience stores have earned their name — their business is built on a grab-and-go model, allowing customers to get in and out of the store in only a few minutes.

C-stores are essential businesses that are key for travelers, locals and those logging miles carrying goods. The last thing any customer or operator needs is to be inconvenienced by poorly maintained equipment. 

Two vital elements in any c-store are coolers and freezers. They serve various objectives, from merchandising sodas and waters to storing food, beer and ice. Walk-ins are constantly under a lot of strain, so c-store operators must set aside time and resources to make sure they avoid costly equipment breakdown.

Below are four best practices that c-store operators should consider to ensure efficient operations when either building a new walk-in or looking to maximize an existing one.

1. Plan Ahead & Consider Functionality

During the design process, c-stores must be proactive and confirm every detail early. Doing so will ensure the entire process, from drawing to installation, goes smoothly.

To begin with, operators must consider the purpose the walk-in will serve as its intended usage will affect specifications. For example, capacity needs, frequency of restocking and volume of stored items affect the required temperature of the designed unit. The type of walk-in, whether cooler or freezer, will influence the thickness of the panels used, which then affects the unit’s total footprint. Additionally, the amount of traffic the walk-in will face will help determine the parts that must be installed into the unit, as durability becomes vital as traffic levels increase.  

C-store operators should determine the walk-in’s colors and finishes, and confirm prints and drawings to make sure that dimensions are correct.

Nailing down these specifications will aid the process and ensure a seamless installation so that c-store operators can quickly begin or return to normal operations. This practice will also make certain the walk-in will be built to last.  

2. Understand Your Footprint & Walk-In Placement

The biggest challenge that c-stores face is space. According to NACS, traditional convenience stores have a footprint of about 2,400 to 2,500 square feet to display a large product mix that includes dairy, snack foods, beverages, health items, beauty aids, and prepared foods to go. Based on these unique footprints, c-stores often require custom walk-ins to fit specific specifications and make the most of their space.

To ensure the walk-in functions correctly, operators must carefully consi­­der placement. C-store walk-ins should be installed at least two inches from opposing walls to allow air to flow between the walk-in and the building wall. This airflow limits the formation of condensation by adding heat into the walk-in surfaces, thereby raising the dew point temperature, and by limiting the formation of water droplets on the walk-in surface from the air’s drying and scrubbing action.

An airflow at a rate of 50 feet per minute across the walk-in wall surface is sufficient to perform the heating and scrubbing tasks. The same airflow principle holds for the top of the walk-in.

Consider the laws of thermodynamics. Without airflow, saturated air can form water droplets on the colder surface of the walk-in panels if the dew point temperature is reached. The dew point temperature on the walk-in is a combination of the air temperature, how much water vapor (humidity) is in the air, and the walk-in surface temperature. In the right conditions, condensation vapor can form on the walk-in exterior surfaces, especially at the connections between the insulated panels, and at the floor and ceiling. These nanodroplets from condensed vapor can eventually turn into mobile droplets, streaming down onto the floor, where it can form pools of water.

If it remains long enough or occurs frequently, that standing water can form mildew and bacteria, which drywall or other porous surfaces can absorb. These materials can become infected with mold, causing significant health and safety issues for the c-store.

It is vital that c-store operators install HVAC systems with proper airflow and temperature/humidity controls to limit the opportunity for condensation formation on the walk-in surfaces — especially the walls, ceilings, and glass doors. Doing so will prevent expensive repairs and extend equipment life.

3. Understand the Impact of Thermodynamics on Cold-Storage Walk-Ins

Cold storage walk-ins are highly insulated envelopes constructed of panels made with insulative foam to resist the flow of heat. The insulation is such a key element of the performance of the walk-in that the U.S. Department of Energy specifies the minimum performance requirements for the insulation. That is because any heat energy that gets into a walk-in must be removed by the refrigeration system, which requires electrical energy.

The better the insulation within the walk-in, the less potential for heat flow within the interior space.

Warmer temperatures and high relative humidity can also impact the performance of the walk-in coolers and freezers. Higher humidity in the walk-in forces the cold storage refrigeration system to work longer to remove it. Sometimes, the refrigeration system can’t keep up, but even if it can, it comes with the cost of inflating energy usage through greater defrost frequency and duration.

Maintaining ASHRAE recommended temperatures and humidity levels will maximize the ability to avoid thermodynamics-related issues. Combining that HVAC control with circulating airflow around the walk-in’s walls and ceilings will go a long way to ensuring walk-ins operate at peak performance.

4. Conduct Routine Maintenance 

Operators should make several checks on their walk-in units on a regular basis. Consistent maintenance will not only extend the unit’s longevity, but also maintain its ability to operate at normal capacity and comply with all National Sanitation Foundation (NSF) standards.

When it comes to cleaning a c-store walk-in, operators must use mild detergent, hot water and a rag to clean the entire unit. Never use a high-pressure hose or large amounts of water to clean a walk-in. Clean the entire unit, including all metal surfaces, the magnetic door gasketing and the door sweep gasket, and then remove all soap film and dry thoroughly with a clean cloth.

Any random spills should be cleaned up immediately as liquids that are kept cold will eventually congeal.

Another important maintenance practice is to inspect parts for wear and tear, as this will impact the efficiency of the walk-in. For example, a gasket that fails to seal will allow too much moisture to enter the unit and either freeze the evaporator coil or flood the drain pan or cooler floor.

Make sure to inspect refrigeration equipment frequently to ensure that evaporators, drain pan heaters, defrost controls and drain line heaters are functioning properly.

To ensure that the walk-in operates correctly, operators must take extra care to make sure walk-in doors are kept closed. Oftentimes, they are propped open while restocking or conducting inventory. While this can be convenient for staff, it stresses the cooling system and, over time, can lead to premature failures.

Walk-in coolers and freezers are built to last, and c-store operators can take simple steps to ensure they operate efficiently in the long-term.

Johnny Wood is national accounts manager for convenience stores at KPS Global. With 27 years of professional experience in the walk-in industry, Wood leverages his extensive knowledge of the industry’s nuances to deliver customizable cold storage solutions for convenience stores, including refrigeration, metal finishes, components (shelving, lighting, etc.), and display doors.

Editor’s note: The opinions expressed in this column are the author’s and do not necessarily reflect the views of Convenience Store News.