An Introduction to Combination Walk-in Refrigerators and Freezers
Combination walk-in refrigerators and freezers have many of the same attributes as single-use units, but have one section that cools between 34 and 38 degrees F and another area that freezes at -10 degrees F.
Walk-in cooler and freezer units can help save space, allowing operators to use one large unit for two types of storage. Like single-use walk-ins, combination units store all types of food items on a large scale.
When a walk-in serves double duty as a cooler and freezer, configuration represents the main difference between the combination unit and two separate units performing single functions. The most common and practical set up is for the main entrance to be into the cooler and the freezer entrance to be in the cooler section. This layout not only helps condition and maintain the freezer's air temperature, but also prevents excess humidity and temperature fluctuations within this part of the unit. Both sections share perimeter walls, and a common wall with a door separates the compartments.
In a combination walk-in, the cooler section typically won't have a separate floor installed, while the freezer area will include insulated floor panels. As with walk-in refrigerators and freezers, combination units are typically custom built.
"Heights vary from the standard 8 feet, 2 inches to more than 30 inches," says William Taunton, president of Gastrotec S.A., Foodservice & MAS Consultants, located in Santiago, Chile, and chairman of FCSI -The Americas Division. "Capacities are unlimited, but I would say the minimum size of a cooler should never be below 60 inches by 60 inches."
Walk-in doors are generally 26-, 30- or 36-inches wide, but 4- and 5-ft. hinged or sliding doors also are available.
Similar to single-use units, panels on combination walk-ins are generally available in a standard 4-inch thickness with either foamed-in-place urethane or laminated polystyrene insulation. Some manufacturers offer 5- and 6-inch thicknesses as options. Thicker panels aid in energy efficiency and are frequently used for outdoor walk-in ceilings that need to support a heavy snow load.
"On the foodservice side of the business, most operators prefer soft nose panels constructed of Polystyrene, Polyurethane or other CFC-free insulating materials," Taunton says. "Internationally, the important thing to note is that not every country [adheres to the same standards] in terms of quality between the panels' locking systems and insulation materials."
Operators can choose from a variety of walk-in panel finishes for the unit's interior and exterior. One of the most popular finishes is stucco galvalume because its embossed pattern helps hide scratches, dents and blemishes that occur over time. Other panel finish options include smooth or stucco stainless steel, galvanized steel and stucco or smooth aluminum. White interior finishes can help brighten the interior space and improve visibility of the food operators store in these units.
Combination units use the same refrigeration equipment as with single-use walk-ins. Remote, packaged and rack systems are available. Chains predominantly use packaged systems, while larger operations, such as big schools and institutions, use remote or rack refrigeration. These units offer standard air-cooled or water-cooled compressors. Though most operations utilize air-cooled systems, hot areas with high outside ambient temperatures may require a water-cooled refrigeration unit.
"Most quality manufacturers of walk-in panels offer between a 5- and 10-year warranty and refrigeration compressors offer up to five-year warranties," Taunton says. "I've seen combination units work like a Swiss watch for more than 50 years in hotels, hospitals and family restaurants."
In terms of options, the selection mimics single-use walk-ins. Operators can add interior and exterior ramps, LED lighting, electronic door open/temperature alarms, view windows, kick plates for doors and panels, pressure relief ports, shelving, heavy-duty or structural flooring, vinyl strip doors, full-view glass doors, anti-sweat modules for glass door walk-ins, rail type wall protectors and membrane and galvalume roof packages.
How to Know When to Replace a Walk-in Refrigerator & Freezer
While they may last 15 to 30 years depending on how well operators maintain their units and several other factors, walk-in refrigerator and freezer units show a number of signs that they be near the end of their service lives. Here we take a look at four indications that it might be time to replace a walk-in refrigerator and freezer.
- Reliability issues: When the refrigeration unit fails constantly leading to inconsistent temperatures, the foodservice operator should consider replacing the unit.
- Running inefficiently: Frost build up on interior panel surfaces typically indicates the walk-in unit is unable to hold the appropriate temperatures for food storage. Because this can compromise food safety, a new unit is most likely justified.
- Penetration of walls and floor: Deterioration can occur with heavy use over time. Damaged panel joints can allow cold air to escape. This can result in a pricey loss of energy over the long term and represents a sign the end of the unit's service life may be approaching.
- Doors not closing properly: A big issue with walk-ins is improper door maintenance. Damaged doors typically do not seal properly and if the unit is more than 10 years old, it may be time to replace the unit.
Walk-in Refrigerator & Freezer Applications
Walk-in refrigerator and freezer units can save on space, as they take the place of two pieces of storage equipment.
Foodservice operators can use walk-in coolers and freezers indoors or outdoors to hold virtually any product, including meat, produce, wine, beer, prepared food and even dough at food-safe temperatures.
"These units are commonly used in pastry areas, cold and hot prep rooms, dessert prep rooms and for holding finished products," says William Taunton, president of Gastrotec S.A., Foodservice & MAS Consultants, located in Santiago, Chile, and chairman of FCSI -The Americas Division. "[Other uses include] as a mobile phone antenna equipment shelter up in the Andes mountains or as a dormitory in Antarctica. The uses are unlimited."
"With larger facilities, like colleges and hospitals, three to four compartment walk-ins are specified more often," says Scott Hester, partner at Refrigerated Specialists Inc., a company that services commercial foodservice equipment located in Mesquite, Texas. "While a casual dining establishment would have a refrigerator and freezer walk-in combination and then a single walk-in closer to the bar that contains beer."
Maintaining a Walk-in Refrigerator & Freezer
Combination walk-in refrigerators and freezers require the same basic maintenance requirements as single-use units. Here are five basic cleaning and maintenance requirements foodservice operators will need to follow to keep their walk-in refrigerators and freezers running effectively.
As with single-use units, proper walk-in maintenance is crucial with combination units to maximize the equipment's service life and energy efficiency. Below are basic requirements for cleaning and maintenance, but foodservice operators should also follow the manufacturer's recommendations.
- Regularly clean a walk-in's cooler and freezer sections should with a sanitizing solution of 4 oz. bleach to 1 gal. of water. Rinse the cleaned area with water.
- In the freezer section, use damp, not wet, mops to clean cooler floors. Excessive water not only will freeze on floors creating slippery conditions, but also can get in the floor seams and walls, causing damage. Instead, sweep freezers with a broom.
- At least quarterly, thoroughly vacuum condensers. Dirt or debris blocking a condenser can cause the unit to overheat and fail. If the compressor fails during the warranty period because it was not properly cleaned, the manufacturer probably will not cover this claim.
- Regularly check evaporator fan blades to ensure there are no nicks that will compromise operation.
- Each month, visually inspect doors to check for torn gaskets and seals, which can leak energy.
- In addition to daily, weekly and monthly maintenance tasks, units should be regularly serviced by a certified refrigeration technician.
Spec Check: Walk-in Refrigerators & Freezers
Like single-use walk-ins, combination walk-in refrigerators and freezers can be custom configured for a wide range of uses. Here are a five considerations operators should weigh when purchasing a walk-in refrigerator and freezer.
The biggest advantage of utilizing a combination walk-in versus a single-use model is the elimination of a wall, which reduces the unit's cost and space needed.
"A walk-in refrigerator and freezer is an essential piece of equipment, so durability, quality and efficiency should be considered," says William Taunton, president of Gastrotec S.A., Foodservice & MAS Consultants, located in Santiago, Chile, and chairman of FCSI -The Americas Division. "Operators who try to save money [when specifying these units] regret it and expend money in operational costs for years."
Storage Requirements & Use
Determine temperature requirements, the types of products the operation will store and the amount of food the unit needs to accommodate to see if a combination unit is appropriate. Operators also will need to consider if space requirements will stay the same or expand, and if it might it be necessary to move the walk-in in the future.
"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," says Scott Hester, partner at Refrigerated Specialists Inc., a company that services commercial foodservice equipment located in Mesquite, Texas. "As a result, the hot air changes the walk-in temperature and refrigerated food temperatures are compromised."
Operators should ensure that the walk-in's size is appropriate for storage needs. If the operation has different height requirements for the cooler and freezer, then a combination unit would not be the right choice. "Operators typically undersize these units and try to save money in accessories and quality by purchasing the cheapest equipment," Taunton says. "With walk-ins, proper specifications are essential."
"Panels can be assembled with different materials or poured in place, but we have used insulated concrete in some cases," Taunton says. "Cost, availability and freight accessibility [need to be taken into account."
"Today, especially in Europe, everything has to do with efficiency, so quality of insulating materials, high efficiency evaporators and condensing units or glycol packs, are the trend," Taunton says. "In the U.S., however, most clients look for [durability], since efficiency is not a real issue yet. In Latin America and undeveloped [countries], everything is based on price."
Doors & Floors
If staff frequently open and close the doors, a heavy-duty door may be necessary. Automatic closing devices, like Cam-lift hinges and a positive door closer, ensure that doors aren't accidently left open. Walk-ins used for display purposes should have glass doors. If staff will use rolling racks or carts within the unit, the operator should specify 30- or 36-inch doors. Specify a reinforced floor, or even a structural floor, if there will be heavy-loaded carts or hefty shelving inside the unit.
"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 days. "We often get calls that there's ice in 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."
Energy Efficiency Considerations for Walk-in Refrigerator & Freezers
Combination walk-in units prevent the loss of cold air in the freezer compartment, since it is adjacent to the cooler section rather than to the kitchen.
Because freezer sections in combination walk-ins connect to the cooler rather than the kitchen, these areas do not get exposure to warmer kitchen air, which enhances energy efficiency.
Most of the green innovations in this category have impacted refrigeration systems. For example, compressor valve train changes offer a 10 percent to 25 percent higher Energy Efficient Ratio or EER.
One of the newest energy efficient developments is defrost on demand, which minimizes the amount of time refrigeration systems go into the defrost mode. Compared with traditional systems that create and distribute heat inside the walk-in, which can create giant temperature variations, defrost on demand disperses heat more efficiently. As a result, the compressor doesn't have to work as hard to get temperatures back down. Not only do these systems help save energy, but this technology can increase the longevity of the compressor.
New technology reduces fan speed when the unit is off cycle, which helps increase energy efficiency.
New hydrocarbon refrigerant technology utilizes CO2 and LP gas, in addition to environmentally-friendly glycol systems. Although not yet in use due to the high cost, manufacturers predict these will become standard refrigerants in the future.