Ever wonder why water beads on the side of a cold drink in the summer but not the winter? Ever wonder why its so dry in the winter, even though there is snow on the ground? The reason is “simple” and the science behind it is called psychometrics, and this short paper is to give a basic understanding.
Hopefully you should be familiar with the term relative humidity, and its definition is the amount of moisture in the air, relative to how much it can hold. This is different from another term which is absolute humidity, which is the physical amount of moisture in the air.
In a nut shell, picture air as a container, and the warmer the air, the larger the container. The scientific reason behind this thought is that air is made up of molecules and since heat is energy, the warmer the air, the more the energy the molecules have. When the molecules have more energy, they move further apart. The more distance there is between the various molecules of air, the more room there is for water to be stored. So, as you cool air, the relative humidity goes up, and when you heat the air, the RH goes down. When you cool the air, the air molecules move closer and the free space decreases. If the air cools down too much, you will hit the dew point, which means the water will literally come out of the air. This dew is the “sweat” you see on the side of a cold drink, or the condensate (water), that you see coming out of your air conditioner or under your car (a/c) in the summer. The opposite is true in the winter, as when you heat the air, the space for water increases so the RH will go down. So if is snowing, the RH outside is near 100% outside but as soon as you open the window that 30 degree air becomes 70.While the absolute humidity (moisture) remains the same, the relative humidity will drop and the warm air will be dry. The only way to increase the humidity is to use a humidifier.
4 oz is the absolute humidity (or dew point)
Each container represents different temperature air. The larger container is warmer air, smaller is colder air. The 4 oz in each container fills a different %. This represents relative humidity
Please call Engineered Air Solutions with your application of humidity control- dehumidifying in the summer and humidifying in the winter. There are many ways to achieve this in both precision, first cost and operating cost.
