One Size Doesn’t Fit All When It Comes to Defrost Duration and Cycle Times

To keep walk-in coolers and freezers operating efficiently, it’s essential to determine their appropriate defrost cycles. However, local climates and the way in which the unit is used greatly affects the optimal defrost cycles and duration times. Let’s take a look at some factors to consider.

Refrigeration systems not only remove heat from their interiors but dehumidify the air as well. As humid air enters a unit, a heat exchanger known as the evaporator removes moisture b condensing on the evaporator coil. Due to the evaporator’s low surface temperature in freezers, moisture freezes on its coils. As frost and ice accumulate, it interferes with air flow and degrades the efficiency of the evaporator, making it difficult to maintain box temperatures which can result in spoiled goods. It is essential that the evaporator unit be periodically defrosted to remove the ice from the coils.

The number and duration of defrost cycles varies and is an adjustment that should be programmed during the unit’s initial set up. Depending upon the region and application, normal compressor shut off periods for coolers may provide adequate time to keep the evaporator coil clear of ice.

In the majority of applications, a timed or auto-defrost cycle is necessary to keep the evaporator coil clear of ice. During the defrost cycle, the compressor is shut off and a small heater in the evaporator is then used to melt accumulated frost from the finned coil surface. As the ice is melted from the coils, the resulting liquid water is caught in a drain pan and removed from the unit via a condensate drain. A p-trap should be used on the drain line so that air cannot enter the unit. In addition, it is critical to optimize the duration of the defrost cycle so it completes once the ice has cleared the coils. If the defrost cycle runs too long, excess heat will be added to the box in the form of water vapor. This water vapor can condense on the ceiling and will freeze, creating pebbling of ice on the ceilings. In successive cycles, this moisture will drip down from the ceiling to the floor, resulting in a dangerous, slippery frozen floor.

The region of the country can greatly affect the required defrost cycle times and durations. A humid area, such as the Southeast, for example, may require more frequent and longer defrost cycles than an arid region like the Southwest. The use of the unit will also affect defrost cycle requirements. If the doors are frequently opened for long periods of time to load the unit, moisture can enter and remain inside. This moisture builds up as frost and ice on wall, ceiling, evaporator and product surfaces. Installing strip or air curtains to keep warm air out can help, as well as programming the fan to cut off whenever the door is opened.

It can be challenging to determine the optimal defrost cycle times and duration for your commercial walk-in cooler or freezer. Working with your local refrigeration expert to determine this will be key to ensure that units are operating at peak efficiency.

With almost 200 years of combined construction and installation experience, KPS Global® is the industry-leading manufacturer of insulated panel systems, supplier of aftermarket parts and replacement equipment, and provider of seamless installation services. Their cutting-edge innovation and unyielding commitment to customer satisfaction, allows them to deliver solutions for the supermarket, convenience store, scientific, and industrial markets.

Learn more at https://kpsglobal.com/

Follow us on social media for the latest updates in B2B!

Latest

Grocery Store Prepared Meals
Consumers Want More Grocery Store Prepared Meals. How Should Grocers Adapt?
December 6, 2022

The consumer dollar has spoken: the best thing since sliced bread is sliced turkey. A new FMI report, the FMI Power of Foodservice at Retail, seems to show that deli-prepared food purchases are up 9.3% compared to 2019 numbers and up 2.4% year-over-year in unit sales. It’s clear that consumer appetite for grocery store prepared […]

Read More
Robotics in Early Learning Can Be Essential in How Students React to STEM Literacy
December 6, 2022

Early learning robotics can be essential in how students react to STEM literacy and with large gaps In STEM achievement persisting across the U.S., access to technological resources can make a significant impact. K-12 education was disrupted by the COVID-19 pandemic, but the disruption could be mitigated by introducing the latest and innovative technology into […]

Read More
The European Space Agency Lunar Launch Programs and Service Initiatives to Watch in 2023
December 6, 2022

The European Space Agency is making strides in its efforts to commercialize space, with a focus on sustained exploration. What are they doing to achieve this? According to the ESA, it all starts with service initiatives. A recent panel discussion at the Space Tech Expo in Bremen, Germany revealed that the ESA is growing its […]

Read More