Door Ajar Alarm Saves Energy in Walk In Refrigeration

(07/07/2007)

We’ve all seen the sign on the local supermarket walk in freezer, or if you work in foodservice, perhaps at your job. That sign varies from place to place but invariably caries the same message: “Close the Door”. That same sign is posted in our schools, restaurants, supermarkets, prisons, laboratories, etc.

All of this would be fine except for one problem: If it’s in your store, it’s costing you money. How much money? That’s a hard question to answer. It depends on your refrigeration system, your utility costs, your walk-ins size, how long your employees leave the door open, etc.

The refrigeration industry has often responded to this halfheartedly, if at all. Some walk-ins have spring loaded doors, but all too often the problems occur when doors are left slightly open anyway or when things are used to block the door’s path.

Temperature monitoring is an important part of loss prevention for refrigeration, yet many refrigeration companies still sell walk ins with no temperature monitoring. Those who have temperature monitoring are only doing something about the most extreme of conditions, when doors are left open long enough to compromise product integrity. Even integrated control systems with contacts to monitor door status often rely on a warning that is sent to a central monitoring station and back again, often through multiple parties, and is all too often ignored.

This has led the industry to find their own solutions to ensure problems are stopped before they’re started: At the door itself. This has led to the inevitable “close the door” sign mentioned above. But it’s also led to a new movement by refrigeration technicians, maintenance, and contractors to find new solutions that take advantage of available technology.

These solutions can be as simple as wiring up a pair of magnetic contacts to the door and providing an audible alarm when they separate. One company, Modularm Corporation from Commack, NY, has been taking notice. They have been meeting this challenge head on over the past few years with their patented DAC-55 Door Ajar Alarm, which sets off a visible and audible alarm when the door is open for a set amount of time.

Their solution goes above and beyond the issue of energy lost to doors being left ajar, addressing a host of energy issues with walk-in refrigeration. The alarm senses light status relative to the door, ensuring lights are off when the walk-in is not in use. It also ties refrigeration functions such as fans and solenoid activation to door status, ensuring that when the door is open, refrigeration isn’t wasted blowing out the door. An optional IP-1 Pushbutton placed inside the walk-in increases its functionality to allow for panic / entrapment alarm in the case of an accident.

While it’s not likely that those signs will disappear over night, companies like Modularm will be providing the wise manager with the means to protect their walk-ins from wasting energy. The company’s internal research as well as several field tests has found that the DAC-55 can reduce the amount of time walk-ins are left open by as much as 86% and the amount of time lights are on by as much as 99.5%.

Related categories:  Commercial and offices applications   Energy Conservation   Refrigeration 

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