Shell and tube heat exchangers are widely used for various industrial refrigeration applications. This paper summarizes previous studies performed on single tube and bundles and the correlations thereof developed for ammonia. There are limited studies available on ammonia boiling outside single tube and bundle. The major driving force behind this paper is that an extensive work is currently underway on the subject of direct expansion of ammonia on the outside of a tube bundle by the authors. As of now, there are no such studies available in the open literature. In order to understand the process, it is important to follow up on previous studies on pool and convective boiling on single tubes and bundles with ammonia.