Condensate Observation Test

Introduction

Desiccants are used to absorb moisture to create and maintain a dry environment that prevents mold, mildew, and rust. They are especially useful in storage areas without temperature control as any water will undergo thermal cycling. When the water vapor condenses it carries contaminants that cause corrosion and contamination. There are different types of desiccants that work in different ways to lower humidity. This experiment directly compares two desiccant solutions: silica-gel granules and Steel Camel Moisture Hog through a simulation of the desiccants in action. This experiment simulates the use of desiccants in a sealed environment where we can see how the moisture accumulates or decreases. 

Objective

​Condensate Observation Test (COT) is a test designed to observe the effect of desiccant bags on condensation in a closed container subjected to thermal cycling.

Results

​After setting up the desiccant bags in the jars, the jars were set out in a covered patio countertop. The jars were logged at approximately 12 hour intervals to observe the thermal cycling of water and the effect of the desiccants. The control jar had a consistently large amount of condensation and water at the bottom of the jar. There are also many water droplet tracks as the water condenses more and more. The Steel Camel jar remained dry the entire experiment. The water did not condense at all on the walls of the jar, only remained at the bottom, and eventually dried up completely. The water took longer to condense in the silica jar than in the control jar, but it did eventually mist over and from small drops. There also did remain a small amount of water at the bottom of the silica jar, although less than the initial amount put in. 
 
Set up desiccants, ensure they have same sized packs and same weight:

​Example of desiccant attached to lid:

Day 0:

​The jar on the left is the control jar so we can observe the behavior of water without the effect of a desiccant bag. The jar in the middle contains the Steel Camel Moisture Hog. The jar on the right contains the silica beads. 
 
After 13 hours:

​The control jar has a lot of condensation on all walls of the jar, enough to leave some water droplet paths. The Steel Camel jar is completely dry and shows no change. The silica jar is also dry, although the silica is noticeably pink through the bag. Water level has decreased in Steel Camel and silica jars. 
 
After 25 hours:

​The control jar continues to have a lot of condensation and more water droplet paths. The steel Camel Jar remains dry and shows no signs of condensation. There is very little water at the bottom of the jar. The silica jar has developed a mist. The water at the bottom of the silica jar has not decreased further. 
 
After 36 hours:

​The control jar has many water droplet paths and still has a lot of condensation. The Steel Camel jar is completely dry, no water at the bottom of the jar. The silica jar is still misted, the water droplets are slightly larger. Some water remains at the bottom of the jar. 

​Steel Camel had gained 4.8 g of water weight by the end of the experiment, so 96% of the water. The other 4% may have been absorbed by the string holding up the desiccant bag. Both desiccants were secured in the same manner, and approximately the same depth. The bag is not damp and the desiccant in the bag is puffed up, resembling the fitness of a tightly stuffed plushie. 

The jars were monitored for a couple days further than the images included in this report to ensure there were no further major changes. In this time, the silica bag had completely molded. The silica absorbed 3.4 g of water and did not prevent mold. All the beads inside are bright pink, indicating saturation point. 
 
 
 
The relative humidity in the inside of the jars is the humanity at the time the jars were sealed, approximately 45.8%. 

Value	Sunday (first 24 hour period)	Monday (second 24 hour period)	Tuesday (third 24 hour period)
Temperature High	90.1°F	89.6℉	83.3℉
Temperature Minimum	77.5°F	80.1℉	77.7℉

Discussion

​At the start of the experiment both jars with the desiccants remained dry while the control jar immediately misted and was covered in condensation. While the silica seemed promising as a desiccant, it underperformed as time went on. The Steel Camel held up better the entire duration of the experiment. The difference in behavior between the two desiccants are the way they actually interact with water. The silica beads are made to maximize surface area and have millions of microscopic pores, which both make use of water’s natural absorbency and capillary action. The water molecules are attracted to the beads and fill the tiny pores in each bead. This means that the beads will only absorb a certain amount of water and the water molecules will  continue going through thermal cycling in the bead. Steel Camel Moisture Hog on the other hand is a polymer type desiccant. The desiccant chemically binds to water, so the water is not free at all and unable to go through thermal cycling.