to increase the use of direct contact processes, the National Science Foundation sup- ported a workshop on direct contact heat transfer at the Solar Energy Research Insti- tute in the summer of 1985. We served as organizers for this workshop, which em- phasized an area of thermal engineering that, in our opinion, has great promise for the future, but has not yet reached the point of wide-spread commercial application. Hence, a summary of the state of knowledge at this point is timely. The workshop had a dual objective: 1. To summarize the current state of knowledge in such a form that...