Delta air conditioner control panel9/25/2023 ![]() Ok, so what should the ΔT be then? Assuming a given airflow and proper refrigerant charge, it depends on the temperature and water vapor content of the air entering the evaporator coil. To consider the latent heat removal and provide an intersecting point, the calculation has to go a little differently this way, we would be working with the total capacity. It would only, however, predict the dry-bulb temperature. The rate of removal between sensible and latent is called sensible heat ratio (SHR) you can read more about it HERE, and please, take the time to read the two comments below the article (especially the first the one by Jim Bergmann), as they offer a simpler way to project the supply air temperature. In providing human comfort, air conditioners are not only tasked with removing sensible heat there is also a good chunk of latent heat removal that has to occur-at least here in South Florida. When we measure ΔT, we only measure how much sensible heat was removed from the return air. Creating, like this, some bad habits of our own. If we measure ΔT while diagnosing a system, and it happens to be at a range that has been deemed acceptable by lack of information and bad habits, we’d be poised to make avoidable mistakes repeatedly. However, because it’s so simple to do and it doesn’t require a particularly expensive tool to measure it, there is a lot of abuse and misuse of it. I said misleading! Don’t get me wrong getting an accurate measurement of what the ΔT is on an operating system has a lot of value. This is one of the most established and misleading rules of thumb in our industry. Heck, I’ve heard some insist that the ΔT across a properly operating air conditioner should always be 20 degrees, even if it were installed in the middle of a football field! No, really, that's quite literally a true story. ![]() Actually, depending on who you ask, the answer will range between 18-22 degrees Fahrenheit. ![]() We are referring to the air temperature drop across an air handling unit or evaporator coil in cooling mode. What do you mean!? 20 degrees, of course! ![]()
1 Comment
12/12/2023 02:03:20 am
This article about air conditioners is incredibly informative! It brilliantly explains complex AC workings in a simple, engaging manner. Kudos to the author for demystifying AC technology effortlessly!
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