Where does the cold air come from? In West Africa, if you're in enough sun to power the motor, isn't the air that's circulating going to be hot? Then you're trying to work inside a convection oven. Cooling garments for use under protective clothing are available now. Could the solar fan be used to help circulate the air to the whole body?
Keep in mind that the primary purpose of a medical protective garment is to prevent the passage of blood and other organic contaminants. Just because a garment repels water, that doesn't mean it protects against bodily fluids. Tyvek, for example, is a chemical protective fabric for inorganic liquids. Companies that make PPE have developed and are marketing garments with breathable fabrics.