
To answer it, we will take you through the following topics:
- Test the desiccants in the same environment
- Buy samples in the open market
- Considerations about loading conditions
- Compare desiccants with the same mode of installations
Test the different desiccants in the same environment
Tests should preferably be made under field conditions to truly reflect reality. Whether you test in real-life or in a climate chamber, make sure test samples are tested in the same environment, either in the same container or in the same chamber.
But what are the differences between a climate chamber test and a real-life test?
Climate chamber test
A climate chamber test is an artificial way of testing the desiccant absorption performance. The advantage is that this test easily can be made in a short amount of time to a relatively low cost. However, the results generated leaves an array of important parameters out.
A climate chamber test often has a duration of 30 days. Both temperature and humidity are set to constants, often 30°C and 90% RH (relative humidity). As a result, moisture inside the climate chamber is always present – it is added automatically and set to be constant – and the desiccants will have unlimited amounts of moisture to absorb.
Consequently, the absorption levels reached in climate chambers can be very high (500-600%).
Real-life test
A real-life test is a test performed inside a container being shipped from origin to destination. In a real-life test, the amount of moisture will be reduced over time as the desiccants will absorb moisture inside a container or polybag. That is what they are designed to do.
Moreover, the temperature will vary when passing through different climate zones and changes during night and day. The relative humidity will also vary, in comparison to the constant relative humidity in climate chamber tests.
In a real-life test, the availability of moisture will be much less compared to a climate chamber test. Consequently, the absorption capacity in a real-life test will look inferior to absorption capacities in a climate chamber. But the reality is:
• Climate chamber and real-life absorption are two completely different things. Desiccant performance during climate chamber conditions can be boosted artificially to reach high and appealing absorption rates. How? Increasing the test duration, the temperature, or the relative humidity.
• Climate chamber absorption levels will never occur in real conditions.
– 400% absorption in a climate chamber could be equivalent to 200% or even less in real life, due to lack of moisture to absorb.
– The absorption in a real-life test could be very low. Simply because there is very little moisture to absorb.
This is similar to the measuring of the fuel consumption of a car. If measured during downhill cruising, the results will be fantastic. However, we are all aware the consumption will be much higher when driving normally.
To underline the headline of this Insight – make a comparison based on the same test method. And never mix the two.