THE DESIGN
Food Bag with Desiccant
The group who worked on a similar project last year developed a design for a plastic bag that would be kept underground. The design incorporated calcium chloride as desiccant, but further experimentation needs to be done to determine whether or not this desiccant can protect food from up to 90% relative humidity. Our design also attempts to address rodent infestation prevention.
DESIGN MATRIX
This decision matrix identities the values of our prospective villages. While the "pot-in-pot" received the highest score in terms of the best opportunity, we decided to conduct further testing on the "bag-in-pot" design since there was more previous research done on this design and we wanted to start off simple.
PREVIOUS GROUP'S PROTOTYPE
For our design, we created a 100%-relative humidity environment by filling the bottom of a plastic tub with an inch of water. Then, we filled three Ziploc bags with flour, a desiccant pouch, and a humidity probe and taped the bags on separate sides of the tub. The humidity of the environment inside the plastic bags was checked every day using the humidity probes. If the flour remains safe to eat after being stored in this environment, then this food storage method may be an effective solution.
DESIGN OF TESTING ENVIRONMENT
Test #1
Three plastic bags with 100 grams of flour were placed in a tub of water with a lid on to emulate a 100% humidity environment. One bag contained 15% desiccant, another 25%, and the last had no desiccant. The humidity of each bag and the tub was tracked with humidity probes to ensure that the manipulation was working.
​
Additionally, the bags were opened for 30-minute intervals and then closed to see the affect of direct humidity on the flour and if the desiccant could deal with a "shock" to it's system.
​
After two weeks, the desiccant was weighed to see if it had absorbed any of the humidity as water weight. We found that the 15% and 25% bags weighed 7.43g and 2.16g more, respectively.
​
The probes were taken out and analyzed once a day during the 30 minute manipulation and data was recorded.
Test #2
A second experiment tested the effectiveness of desiccant after it was exposed to a 100% humid environment for hour-long increments.
Additionally, conditions in this experiment were more controlled than the last. A glove bag was used in place of a tub to ensure that humidity (water vapor) was not lost when the tub was opened during bag-opening manipulation.
​
This set-up was similar to the last experiment but with only two bags of flour. Similarly, one served as a control with no desiccant. The other bag contained 25% desiccant. Again, a probe was placed in each bag and in the environment to ensure the manipulation was taking place.
​
The experiment occurred over a week and the bags were opened once a day for an hour. The probes were removed and data was recorded at the end of the week.
