Research on Microclimate Cooling in protective clothing is not a new topic. Yet we are not able to provide cooling to the health care workers. In this research contribution I try to give some information on where the problems are.
thanks for updating the post. I still wait for a quantitative description of the problem (How hot is the environment really, how active are the workers) and on experiments. I am quite sure, that someone makes this, but all people I asked do not know about this. So we will probably learn this in a few month.
And to do measurements ourself to evaluate and improve is difficult without a climate chamber and other tools. And again, I would not even know how hot I shall make the climate for the tests. The resources of USAID appear so limited, that they have no time to give us feedback by experts. And if I try to help you, this takes even more from the limited time, I have for making and proposing own ideas. So, I am sorry, but I cannot help you as much as I would like to.
it is the same like sweating. If water evaportates it requires energy, the latent heat of evaporation. This energy is taken from the liquid and cools it.
The same works with liquid cryogenic gas. Just leave the bottle open, the liquid evaporates and cools the liquid. We do this routinely in laboratories. But typically not with liquid air, but with liquid nitrogen. Liquid air is not so easy and safe to handle as liquid nitrogen, but you can get and use it, if needed.