I am curious. Maybe I don't understand something, but many articles I come across perform an energy balance on a solid and on a liquid. **I assume evaporation acts on the remaining liquid and not directly on the substrate. Correct?** They always include heat loss due to evaporation as energy loss from the solid but not the liquid. Would it be more proper to perform a balance on the liquid wherein evaporation removes heat (watts per square meter of surface area? simply KJ?) from the water surface, which would then increase convection from the solid substrate to the water itself? THere must be a good reason I haven't once seen it described that way (other than laziness).