On its face, the term “anti-sweat heater” sounds like an oxymoron. Doesn’t heat normally make you sweat? Yes, but we’re not talking about the perspiration that comes from jogging on a hot day. We’re talking about the type of sweat that develops on the glass doors of reach-in refrigerator and freezer display cases in convenience stores and supermarkets. This sweat appears when cold, dry air inside the case mixes with warm, humid air from the store. Sweating creates several problems for store owners:
- It’s harder for customers to see the products inside the case, which can reduce sales.
- More energy is needed to lower the temperature and humidity levels in the display case.
- Compressors work harder and wear out faster, increasing maintenance and replacement costs.
- Mold and mildew can form on gaskets, and door frames can corrode.
In order to combat sweating, most reach-in display cases are equipped with anti-sweat heaters, or ASHs. These heaters are strategically located in three areas:
- Along the edges of glass doors to prevent condensation
- In the door frames to prevent fogging and keep doors from freezing shut
- Within the case frame to prevent moisture build-up
These ASHs do a great job, but they don’t need to run all the time. After all, you don’t run your car’s windshield defroster every minute that you’re behind the wheel – you turn it on only when the windshield fogs up. And that’s where ASH controls come in. Instead of running the heaters 24/7 to do a part-time job, ASH controls monitor temperature and humidity levels inside the case and adjust the heat production as necessary to prevent sweating.
Since anti-sweat heaters only have to operate a fraction of the time – generally about 15 -20% of the day, which is when condensation is present in the display case – equipping ASHs with automatic controls can typically reduce anti-sweat heating costs by 70 – 90%. ASH controls save energy and money in several ways:
- Reduce energy usage: Turning off ASHs when they’re not needed cuts the number of kilowatt hours you use.
- Reduce demand charges: Business owners who pay demand charges on their electric bills can benefit from not having their ASHs running during peak periods.
- Minimize refrigeration costs: The heat produced by ASHs has to be offset by the display case’s refrigeration, so turning off ASHs when they’re not needed minimizes offset refrigeration.
- Extend compressor life: Compressors can last longer when they’re not working round the clock to offset the unneeded heat being generated by ASHs.
Anti-sweat heaters are an important part of keeping your refrigerator and freezer display cases running efficiently and effectively, but integrating controls with these heaters is just as important to make sure they run only when they’re needed. That way, you can help keep your energy costs in check…and save your sweating for the jogging track.