Published on Wednesday, 01 January 2014
Written by The Editors
For operators looking to cut costs and consolidate storage, combination walk-in refrigerator freezers may be a viable option to consider as an alternative to two separate units. Like single-unit walk-ins, combination models are typically custom-made, so these units come in virtually any shape and size.
"With combination walk-in coolers and freezers, there is basically no limit [in size]," says William Taunton, president of Gastrotec S.A., Foodservice & MAS Consultants, based in Santiago, Chile, and Chair FCSI-The Americas. "[The type needed] will depend on the client type, size of the business and space availability."
With average temperatures ranging between 34 degrees F and 38 degrees F for coolers and -10 degrees F for freezers, the size an operation requires depends on how the restaurant will use the unit and its sales volume.
Timing is critical, as ordering these units requires some lead time and installation of a walk-in typically takes place early in a project. Proper installation represents another crucial factor because it helps prevent air leakage, which can produce ice in the freezer section and moisture in the refrigerated area.
Construction of combination units tends to be similar to that of single-use units, and operators can choose from panels constructed with a wood frame box, high-density rail, Polyurethane foam or Polystyrene. "On the foodservice side, most clients prefer soft-nose panels, such as Polystyrene, Polyurethane or other CFC-free insulating materials," Taunton says. Freezers also contain a defrost system to melt frost off of the system's coils.
The equipment's exterior typically features stainless steel, aluminum or galvanized aluminum construction. "The metal can have different gauges as well as different shapes," Taunton adds.
A View from the Field
"If an operator is buying more than one walk-in compartment, and these will be located side-by-side, the dealer will most likely provide a combination box that shares a wall," says Scott Hester, partner at Refrigerated Specialists Inc., a Mesquite, Texas company that services commercial foodservice equipment. "This way, the operator is purchasing less equipment that is accomplishing the same job."
Taunton adds, "Although capacities are unlimited, I would say the minimum size of a cooler should never be below 60 inches by 60 inches. Operators typically under size these walk-ins and try to save money in accessories and [sacrifice the quality] to cut costs. With these types of products, [proper] specifications are essential."
"Today, especially in Europe, everything has to do with efficiency," Taunton says. "As a result, the quality of insulating materials, high efficiency evaporators and condensing units or glycol packs, are important."
Common Specifying Mistakes
Combination units are not recommended for operations that require cooler and freezer walk-ins of different heights, as the amount of wall space will be equal in both.
Because the load put into a walk-in can dramatically affect the function of the cooling system, take into account the size of the condensing unit and evaporator when choosing a unit. "Operators will add a few extra feet onto a walk-in cooler section to accommodate hot foods that need cooling, but they won't purchase an oversized refrigeration system to compensate for the temperature change," Hester says. "As a result, the hot air changes the walk-in temperature and refrigerated food temperatures are compromised."
"Unlike refrigerated walk-ins located on the first story, those used in multi-story applications need an insulated floor to provide a moisture barrier," Hester says. "Walk-in freezers also require insulated floors. We often get calls that there's ice on the freezer, and this means the thermal barrier on the floor was improperly installed. It's important that sizes and dimensions are accurate to prevent an expensive service call."
The following are several other factors to weigh when specifying a combination unit:
- Not only do operators need to determine how much product the unit will store, but also how often staff will stock the walk-in, which depends, in part, on the number of food deliveries.
- Factor in the extra clearance needed for these units. A walk-in will require at least 2 inches of space between the unit and building as well as a minimum of 1 inch on all sides for proper ventilation.
- Determine if space requirements or cooling needs will change or if the walk-in will require a new home in the future. The latter would necessitate cam-locking panels, which provide easy dismantling of the unit.
- Don't forget to take into account the kitchen temperature. If operating in a hot environment, a larger refrigeration system may be necessary.
- "Walk-in refrigerator and freezer combinations are essential pieces of equipment, so durability, quality and efficiency are prime considerations," Taunton says. Operators who seek to save money up front typically regret it, since more money will be spent in operational costs over the long-term. "This is a piece of equipment that will be around for years to come."
- Operators should determine what products the walk-in will store. Depending on an item's density and temperature, it may take longer to pull down to the correct temperature and a larger refrigeration system may be necessary to compensate. In addition, hot product creates excessive steam in cold environments, producing moisture and changing the dynamics inside the walk-in.
- Walk-ins use either single or three-phase electrical power, but larger units may require a dedicated circuit and more amps.
- To figure out the necessary capacity, operators should keep in mind that 1 cubic foot of open storage area accommodates approximately 28 pounds of solid food.
- Operators can choose from panel thicknesses that ranges from 2 to 8 inches.
- Since they receive most of the day-to-day abuse, doors represent an important feature. If staff frequently open and close doors, a heavy-duty option may be necessary. Automatic closing devices, like cam-lift hinges and a positive door closer, ensure the door isn't accidently left open. If it's necessary to see what's inside the walk-in, a view window should be specified. Electric air curtains can be a wise choice, depending on the operation and physical location of the walk-in. There are calculator tools that demonstrate break-even and pay-back analysis.
- Assess the weight and frequency of traffic to determine what type of flooring the walk-in requires. If staff will use heavy-loaded carts or there will be heavy shelving inside, a reinforced or structural floor may be needed.
- If the walk-in will have floor panels, interior or exterior floor ramps can provide easier access.
- Polyurethane panels, because of their greater efficiency, can be much thinner and still meet R-factor requirements. The market that qualifies for foodservice is between 3½ and 5½ inches of insulation, with 4 inches being optimal in most conditions.
- Stucco embossed, whether stainless, galvanized galvalume or 'acrylume', are all suitable for hiding minor scratches, dents and blemishes. Operators should look for a minimum 10-year limited warranty against structural defects.
- White interior finishes can create a brighter environment and make the walk-in's contents more visible. In high-acid environments, such as bulk vegetable storage, consider other metals. Operators should check with a product specialist for more details on how to select metals for these environments.
- The use of low-velocity coils inside a box may be appropriate in certain situations, such as with the use of fresh pizza dough that is not completely covered and delicate produce.
- When specifying boxes where transport carts are often used, such as in schools, catering and corrections, care should be given to specify appropriate bumper systems so as not to prematurely damage or even puncture walls with handles, hinges, bumpers, etc.
- Coated coils may be necessary in high-acid environments.
Considering Features and Options
- Although walk-in refrigerator and freezer options vary by manufacturer, there are a number that are worth considering.
- Interior and exterior ramps can be specified for operations utilizing carts or equipment with wheels for easier access in and out of the walk-in.
- Electronic door open/temperature alarms may be necessary in high-volume operations to ensure temperature consistency within the unit.
- Kick plates for doors and panels, along with heavy-duty or structural flooring and rail type wall protectors can
- provide increased durability.
- Shelving creates extra storage space and helps maximize the unit's height.
- Temperature monitoring and recording systems can help operators comply with HACCP guidelines.
- Evaporator control increases overall efficiency as well as product life and overall
- maintenance costs.
- Motion detector lighting ensures that lights are not left on unnecessarily.
- Bluetooth connectivity alerts operators when appropriate temperatures are not being maintained.
- If it's necessary to see what's inside the walk-in or it is being utilized as a merchandiser in a retail setting, glass doors should be considered.
- Strip curtains are another option and can help keep out unwanted outside air.