1)a sustain able design means that it can be sustained thorough time and it cannot be made in a better version in a few months time and the product will last for about a few years.

2)it could be incorporated in long term areas with a natural problem.

3)the people who are poor had no refrigeration so he decided to come up with this idea to prevent diseases from no refrigeration.

4)the poorer population of mankind could use it as it is affordable to them