The craft brewery industry has seen exponential growth this decade, fueled by consumer demand for full-flavored beers. According to the Brewers Association there are 3,040 breweries operating in the U.S., 99% of which are small, independent craft breweries.1 With thousands more breweries in the planning stages, this trend shows no sign of slowing.
The logistics of how to keep beer cold and fresh before shipping to the consumer is vital to the success of any craft brewer. That’s why Brew Cave by U.S. Cooler is introducing their new line of walk-in coolers for the brewery industry. Brew Cave is best known for its walk-in kegerator for residential bars, but now produces everything from keg storage warehouses to tap house coolers.
Every brewery has unique needs and budgets. Brew Cave’s flexible design process allows them to easily create custom walk-in coolers. Whether the cooler needs to be angled, have reach-in glass doors, operate with minimum sound, be located outdoors or any other special case, Brew Cave is up to the task. Their parent company U.S. Cooler has been in operation since 1986 and its employees have extensive experience catering to a wide assortment of industries from bars, convenience and grocery stores to scientific and manufacturing facilities.
Aside from the box temperature, other considerations that are particular to medium temperature applications (walk-in coolers & refrigerators) are the air velocity and humidity of the refrigerated space. Below freezing, humidity is inherent (the moisture is mostly frozen out of the air), so low temp applications are easier to spec than medium temp.
The following are common design parameters and examples of their application:
35 degrees F / 90%+ relative humidity (low velocity coils) – high humidity – Used for: sensitive materials, floral – roses
35 degrees F / 85% – 90% relative humidity – general purpose – Used for: foodservice, fresh meats, packaged goods not sensitive to humidity, short-term mixed produce, thawing, and dry goods unaffected by humidity
35 degrees F / 60% – 75% humidity – low humidity – Used for: retail, beer and beverage coolers, packaged items, materials sensitive to humidity
45 degrees F / 55% – 70% humidity – low humidity – Used for: aging red wine
45 degrees F / 90%+ humidity (low velocity coils) -high humidity – Used for: sensitive materials, floral – general
55 degrees F / 55% – 70% humidity – low humidity – Used for: processing rooms occupied by personnel
55 degrees F / 60% – 75% humidity (low velocity coils) – low humidity – Used for: produce
When buying refrigeration units for walk-in coolers & freezers, it’s very important that your refrigeration is sized correctly for your box and application. Incorrectly sized refrigeration can result in problems such as the refrigeration unit constantly running and eventually freezing up.
To help you get the right size refrigeration unit, Heatcraft Worldwide Refrigeration has put together a Quick BTUH Load Calculation Chart. It can be used for walk-ins rooms from 6’ X 6’ X 8’ to 40’ X 40’ X 8’ and with holding temperatures of -20°F, -10°, 0°, 30° and 35°. Loads are calculated based on boxes utilizing 4” of urethane R-25 insulation.
Before using these charts, get this information about your walk-in cooler or walk-in freezer:
1. Room information:
•Length, width, and height of the box in feet
•Holding temperature of the refrigerated room (°F)
•Relative humidity in the refrigerated room (if specified)
•Summertime design ambient temperature (°F). This is usually the temperature expected at the location of an air cooled condensing unit which cools the room
2. Insulation information:
•Type of insulation, insulation thickness (inches), and external temperatures on walls, ceiling, and floor.
3. Infiltration load information:
•The temperature (°F) of the entering air and the relative humidity of the entering air. Also, an estimate of the door usage – average, heavy, etc.
•Does the box have glass doors? Dock doors? How many?
I’m Mitch Byrne. I have been working in the Refrigeration Trade for over 16 years. I know from experience that commercial refrigeration maintenance can extend equipment life by years & save big on electrical consumption. This article will explain the importance of Commercial Refrigeration Maintenance. It will also outline basic DIY Maintenance as well as professional clean & checks done by a contractor. It is possible for equipment owners to perform some basic maintenance tasks between contractor visits.
Commercial Refrigeration Maintenance is critical, especially when it comes to Walk-In Coolers, Freezers & Ice Machines. This is especially true when it comes to line coolers. All refrigeration needs to expel heat. The majority of units do this through an air cooled condenser coil. This is done by drawing air through the coil. This causes dust & debris to form fairly quickly on the condenser coil. Failure to clean condenser coils on a regular basis will increase electrical consumption & lead to major system component failure such as burnt wiring, a failed condenser fan motor, a restricted metering device or a failed compressor. These are some, but not all of the possible consequences of lack of maintenance. Without a doubt poor maintenance will decrease the lifespan of equipment & increase electrical consumption.
There are things you can do between contractor clean & checks that can really help. The following is a checklist of tasks you can perform to help extend the life of your commercial refrigeration equipment.
Visually inspect the condenser coil on self contained refrigeration. Often the condenser coil is behind a cover at the top or bottom of commercial coolers & freezers. Condenser coils can also be located at front right or left on a unit & also at the back of a unit. The condenser cover can usually be removed with a Philips screw driver. Occasionally a ¼” or 5/16” nut driver is needed to remove cover. Pictured are a couple types of coolers & condensers.
A systematic approach to walk-in cooler and freezer maintenance is the technician’s best guide.
The ubiquitous walk-in cooler or freezer is an essential part of many cafeterias, restaurants and convenience stores. It is also a large energy user in these facilities but is rarely considered until problems emerge.
Problems include failure to maintain pressure and compressor failure, both of which can result in expensive losses to the products stored in the cooler. These problems, as well as unnecessarily high energy use, can be avoided by observing equipment and taking corrective action.
Evaporators Moisture from the air freezes onto the evaporator coils (the cooling coils in the freezer) and forms an insulating barrier to heat transfer. Airflow also decreases as the passages narrow due to ice buildup. Each evaporator has a defrost cycle to melt frost/ice that has built up on the evaporator coils. Water from the melted ice is drained from the freezer . . . ideally.
To give you a rough estimate of how much it cost to operate a walk-in cooler or freezer, using the national average of $0.1071 per kilowatt, look at the chart below.
Average Cost per month
Average Cost per month
Note: The above figures are estimates in a controlled environment; your exact numbers will vary.
*These numbers were figured using the 12-month rolling average of $0.1071 kilowatt hour cost. According to the Energy Information Administration this is the average cost in the United States for commercial electricity as of November 2014.
This chart was created using several assumptions that can affect your actual operating cost.
The type of insulation in the walk-in.
Efficiency of the refrigeration system.
Inside and outside temperature of walk-in.
Where the walk-in is located.
The temperature and the weight of the product entering the walk-in.
How often the door is opened.
The age of the walk-in.
Cost of electricity.
This is just to name a few. If you would like to be more accurate using your electric rate, follow the instructions below.
When troubleshooting walk-in freezers, technicians often find a frozen evaporator coil. Although there are several possible causes, one common cause involves the defrost system. For some reason, the system is not properly defrosting the evaporator’s coil on a regular basis. In order to effectively troubleshoot this problem, a technician must understand the design and operation of the defrost systems typically used.
One popular method of defrosting walk-in freezers is the electric defrost system. This is comprised of several components, including a defrost timer, resistive heater(s), defrost termination switch, fan cycling control, and drain line heater. An electric resistance heater is placed on the outer surface of the evaporator’s coils. The energized heater supplies enough heat to completely defrost the coils.
The resistive heaters used on a typical electric defrost system are sized to provide sufficient heat to effectively defrost the coil’s surface. Their capacity is normally rated in watts per foot. They are shaped to fit snugly onto the coil surface, creating efficient heat transfer during defrosts.
Most heaters are manufactured for a specific coil, and when replacing these heaters it is best to obtain the OEM replacement. Universal defrost heaters are available, but matching their wattage and shape may be difficult.
A defrost timer controls the entire defrost operation. It initiates the defrost cycle, controls the operation of the compressor and defrost heaters, and is part of the defrost termination. Defrost timers can be adjusted to initiate defrost from just once a day to several times a day.
The actual number of defrosts per day depends upon the location of the walk-in. Walk-in freezers are usually designed to defrost once or twice a day. The more humid and warm a location, the more defrosts will be needed. If a system needs to be defrosted more frequently, add only one additional defrost period at a time and monitor the results. Adding too many defrost periods will not be beneficial to the system or the customer.
In a common wiring diagram for a time-initiated, temperature-terminated electric defrost system the time motor (TM) is energized continuously. Normally closed contacts 2-4 of the defrost timer are wired in series with the compressor and the evaporator fan motor (EFM). Normally open contacts 1-3 are wired in series with the electric defrost heaters and the timer release solenoid (TRS).
The timer motor controls the operation of contacts 2-4 and 1-3. They work opposite each other. When contacts 2-4 are closed, 1-3 are opened. When contacts 2-4 are opened, 1-3 are closed. When the timer motor initiates a defrost, contacts 2-4 will open and 1-3 will close. This stops the compressor and the evaporator fan motor, and energizes the defrost heaters.
As of January 1, 2009, all walk-in manufacturing companies must sell their refrigeration units with Electronically Commutated (EC) motors. EC motors lower energy costs and significantly improve the walk-in cooler or freezer performance. These energy efficient motors are offered as a complete unit or as a drop-in replacement. Whichever your use is, if you are not familiar with the EC motor it may seem odd when you initially start it up.
When starting an EC motor, the motor must know where the rotor is located in order to start and continue to run. When power is first applied to the motor, the controller will apply a gradually increasing amount of current to all three windings in the motor over a period of 2 seconds. This will cause the rotor to move to a known location. This move will range from no movement at all if the rotor has stopped in the location needed for the next start or may be a much larger movement if it was a longer distance from where it needed to be. With a fan blade attached, it may even overshoot and move backwards to get to the right location. After that 2 second “positioning” period the controller will start applying power to different phases in a slow rotating pattern that increases in speed over the next 2 seconds until the rotor is moving fast enough for the controller to be able to detect its location. This second phase of the start cycle usually happens so quickly that you cannot really see what is happening. Within 3 to 5 seconds of applying power, the motor should appear to be running normally, but during those first 2 seconds the movements may seem as though the unit is having troubles starting or is broken.