I hope you got the intentional misspelling of the first word in the title. It’s a bad dad joke thing, but I get accused of that a lot. The word psychrometrics sounds intimidating and it has an even more intimidating definition: the field of engineering concerned with the physical and thermodynamic properties of gas-vapor mixtures. Simply put, it is the study of air and water vapor mixtures. It is an extremely important field of study for HVAC system designers that need to control humidity levels. It is also important to the people, processes, product and equipment that depend on tightly controlled humidity levels for comfort, efficiency, quality and safety. In the first of this three-part series, I’ll start by defining the terms of art. In part two, I’ll explain how to use a psychrometric chart. In the final installment, I will use what we have learned about psychrometrics and apply it to some real-world situations.
Terms of Art
Some of the terms of art for pyschrometrics are confusing, so they are often misused. With the scientific definition and a little explanation from me, you will have a better understanding of what these terms mean.
| Dry Bulb Temperature | Is the temperature of air measured by a thermometer freely exposed to the air. It is stated as dry bulb temperature in pyschrometrics because it is the air temperature that is not effected by moisture. We commonly refer to it simply as “air temperature.” It’s the one that the weathercasters talk about on TV.
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By defining the psychrometric terms we can all start with a common understanding. In the next part of this series, we will explore a psychrometric chart and learn about the relationships between the terms of art that I defined above.