• Contractingbusiness Com Images Archive Mike Murphy

    Cold coils & moisture removal go together like beer & HVAC

    Sept. 1, 2002
    Theres a joke about how the secret of life can usually be captured in various analogies about beer. Early in life I subscribed to that philosophy and

    There’s a joke about how the secret of life can usually be captured in various analogies about beer. Early in life I subscribed to that philosophy and it wasn’t until sometime between a high school party and parenthood that I discovered beer didn’t hold all the answers to life’s great mysteries — though it had come close on numerous occasions.

    In 1986 I signed on for an HVAC tour of duty and found that beer was indeed critical to the success of our industry. I was having a difficult time understanding the concept of the refrigeration cycle. My good friend and mentor, Jeff Britain, sympathetic to my thermodynamically challenged brain, enlightened me over a glass of beer with a long story about beer.

    Air conditioning systems that run hot and cold are much like a guy and gal who meet in a bar. My friend related this to rising temperatures and pressures, etc. Suffice it to say, things get hot between the guy and gal, at first. After way too many cold beers, things cool off substantially — the heat is gone.

    Somehow, this arcane analogy (which was much better in the lengthier, not-suitable-for-a-family-magazine, R-rated version) made some sense that night and I eventually became a test-passing, card-carrying, EPA-certified, Level II refrigeration dude. Scary, isn’t it? See, beer works.

    Later, I learned of the infamous beer can charging method — beer can in one hand, suction line in the other. Sure, weighing in the charge or using some fancy superheat method will work better, but it won’t taste as good as a Guinness. I’ve heard an Irish beer can is preferred by many practicing HVAC technicians.

    I had nearly forgotten beer’s importance to our industry when I was asked to teach refrigeration to my literary peers. You wouldn’t want any of these people swaging a copper line for you, but they’re a lot of fun. I found myself using another beer analogy to explain how more moisture can be removed by running a colder evaporator coil temperature.

    Hold an ice-cold can of beer up in the air on a 95 degree day. The can sweats. Well, not really. Beer doesn’t magically ooze through the aluminum can — that would be a mystery of life. The moisture-laden, warm air is drawn to the cold can. Then, condensate forms on the can. Voila! Moisture is removed from the air, much the same as a colder coil removes more latent load from a conditioned space.

    Isn’t beer great?

    The point of this story might be that if you know what you’re doing you can design cooling systems to effectively control the humidity. Or, that beer has made tremendous contributions to our industry and should be held in high regard.

    If you’re more interested in providing total comfort and humidity control for your customers than in the virtues of beer, consider this testimonial from David Debien.

    Debien is the president of Central City Air, Houston, TX. After warning the Texas Public Utility Commission that high SEER ratings were going to cause problems in the humidity-laden climate of Texas, he applied his real-world knowledge by significantly downsizing evaporator coils in the systems he installed — by as much as two tons — under the manufacturer’s high SEER recommended match. This causes the coils to run extremely cold, which increases the system’s humidity removal capability and prevents mold from forming.

    In an HVAC world gone crazy over mold, what do you think of Debien’s idea? I’d like to hear your thoughts on the subject.

    Mike Murphy, editor-in-chief, at[email protected] or call 216/931-9320.